Ambiguity

escher

Concourse 2

This is quite a long guide with separate sections, not necessarily connected or following on from each other.
If you are here for the first time, and just want to get an overview of the scope of ambiguity and the various classifications we can use, work through it sequentially but if you are returning to check something, here's a list of the contents to take you to its various sections.
Links in bold are to major sections, others lead to subsections.
Clicking on -top- at the end of each section will bring you back to this menu.

Ambiguity is not, of course, a phenomenon which is confined to English. All languages can be used in a way that allows two possible interpretations, sometimes more, of what seems to be a simple enough statement or question.
In English, for example, the following has recently occurred:

He: Welcome home. I've saved you a job.
She: Thanks, that's good of you.
He: Don't be sarcastic.
She: What?!

Task:
What has gone wrong?
Think for a minute and then click here.

The answer lies in the polysemous nature of the verb save. It has more than one meaning although the meanings are clearly connected.

  1. It means set aside for action or use in the future as in, for example:
    I have saved enough money for my holiday
    I have saved the best idea till last
  2. It means avoid having to use or do as in, for example:
    I have saved an hour's work by using the new program
    She has saved the company lots of money
  3. It also means rescue as in, for example:
    She was saved from drowning
    The castaways were saved by a passing fishing boat
    of course but that is not relevant here.

What has happened in this little dialogue is:

What we have is an example of lexical ambiguity inherent in the polysemous nature of the verb.

Many of the examples below are culled from other guides on this site in which ambiguity is considered almost in passing. Here, it is the focus.

Sources of ambiguity

This guide considers three main possible sources of ambiguity, explains what the problem is and tries to suggest some ways to remove the ambiguity. The three are:

    Lexical ambiguity
    The source for this is the fact that some words have homonyms which look and sound the same but carry different meaning.
    In spoken language, homophones will have the same issues and in written language homographs may also be a source of ambiguity.
    The issue we saw above with the word save is not, however, to do with homonymy; it concerns polysemy, the phenomenon of words have different but connected meanings rather than different and unconnected meanings. The borderline between homonyms and polysemes is, however, somewhat blurred.
    There is a guide to the polysemy, linked below in the list of related guides at the end.
    Here are some examples of what is meant:

Issue Example Meaning 1. Meaning 2.
homonymy They found the quarry They found the animal they were hunting They found the source of building stone
polysemy What did you read last year? What did you study at university? What reading did you do last year?
He may come He has permission to come It is possible he will come
grey area She took a taxi She used a taxi as transport She stole a taxi
homophony The border / boarder is here The edge / frontier is here The paying guest / tenant is here
homography He bought a new bow He bought a new violin accessory He bought a device for shooting arrows
Issue Example Meaning 1. Meaning 2.
modification I said I would come on Monday I said this on Monday I will come on Monday
Being honest, he was seen as rude My honest opinion is he was seen as rude Because he was honest he was seen as rude
independence I washed the car in the corner I washed the car which was in the corner It was in the corner that I washed the car
I spoke to the man in my office I spoke to the man who was in my office It was in my office that I spoke to the man
tense form I'm driving to London this week Sometime this week I will drive to London It is my temporary habit to drive to London
The professor is writing to the students The professor is currently writing The professor intends to write
conjunction She was exhausted but Mary worked on Mary and she are the same person Mary and she are different people
Someone stole my car so that I had to take the train The result of the theft was that I took the train The purpose of the theft was to force me to take the train
Issue Example Meaning 1. Meaning 2.
who does? John and Peter have a house in London John and Peter share a house in London John and Peter have separate houses in London
what is the object? John used his own car and so did Mary Mary and John used John's car Mary and John used their own cars
limitation The tiger is a dangerous animal This particular tiger is dangerous Tigers are dangerous
what is the subject? John saw the boss and he asked him to wait John asked the boss to wait The boss asked John to wait

At the end we will also consider a fourth source of ambiguity which is not dependent on language use but which stems from social and cultural sources.

Lexical ambiguity

It is quite rare for a lot of polysemes and homonyms, especially those concerning content words, to cause a great deal of difficulty because the context almost always determines the meaning that is meant.
We are unlikely to misinterpret, for example:
I took an aspirin
as
I stole an aspirin
or
She dug the garden
as
She appreciated the garden
although misunderstanding is always possible if the context is too thin.

Function words and auxiliary verbs are a very different matter because the meaning they convey relies on the co-text.
Here are some examples but no guide to ambiguity can ever cover all the possible sources.

will and other modal auxiliary verbs

The verb will is polysemous because it applies to a future time in one sense and to a current willingness in another. So,
Will you marry me?
concerns the woman's current willingness to commit to something, but
Will she marry him?
is a question requiring speculation about the future.
In the first example, the modal auxiliary verb refers to dynamic modality (volition) and in the second to epistemic modality (propositional truth).
That is the reason that will can appear in both parts of a conditional sentence such as:
I will give you a lift if you will share the petrol costs
Normally, the rule is not to use will in both clauses but it is correct here because the first incidence of will refers to the future and the second refers to the hearer's willingness to do something.
It is only useful to tell learners that we cannot use will in both parts of a conditional sentence if we are clearly using the verb in one of its main meanings. In other words, being careful to avoid ambiguity.

A fundamental reason why modal auxiliary verbs cause so much trouble for learners is their polysemous nature.
Here are some examples of what is meant:

Verb Example Meaning 1. Meaning 2.
might She said they might ask questions at the end She gave them permission to ask questions She thought it was possible they would ask questions
may They may go They have permission to go They might go
He may not come I will allow him not to come He might not come
can Can you help her with her homework? Please help her with her homework Are you able to help her with her homework?
You can talk to him I give you permission to talk to him He is approachable
†I can not smoke I have the ability not to smoke I am not allowed to smoke
would He would be rude to his mother if she asked a question He was habitually rude to his mother when she asked a question If his mother asks a question his response is likely to be rude
could She could explain it more clearly She was able to explain it more clearly She should explain it more clearly
It could bend It has a flexible nature / ability It is possible that it will bend
I could have left it with John John gave me permission to leave it with him It is possible that I left it with John
If you come late you could miss the speeches It is possible you will miss the speeches You will be able to miss the speeches
ought He ought to be there I expect he is there He has an obligation to be there
must He must be at home I am certain he is at home He is obliged to be at home
have to He has to be at home
† This ambiguity cannot occur in writing because can and not are written separately in Meaning 1.

The moral is that all modal auxiliary verbs have the possibility to be interpreted in multiple ways.
Elsewhere on the site, the verb could is shown to have eight possible meanings (present possibility, future possibility, past possibility, present ability, future ability, past ability, permission, complaint), might has six (present possibility, future possibility, past possibility, suggestion, permission, complaint) and even should has four (advice, obligation, conditional uses, logical deduction).
Other modal auxiliary verbs, especially the central nine, suffer from the same ambiguity of modality type.

adjectives

Scope
radio

This sentence:
The hardworking students passed the examination
is ambiguous because this may mean either:
The students who worked hard passed the examination
(and other students, less hardworking, did not)
or
The students, who worked hard, passed the examination
(all of them were hardworking and all of them passed)
Other adjectives are open to similar multiple interpretations. For example:
The available money is inadequate
in which the adjective available can mean:
all the money (with no more to come)
the money available now (with more to come)
This can be disambiguated in two ways:

  1. By making a relative pronoun clause and distinguishing between defining (restrictive) and non-defining (unrestricted) forms:
    The money, which is available, is inadequate
    (i.e., it is all available)
    vs.
    The money which is available is inadequate
    (i.e., only the money which is available, not all of it)
  2. By post-positioning the adjective:
    The available money
    all of it
    vs.
    The money available now
    some of it with more to come

The second disambiguation trick works with other adjectives as in:
The visible stars
The stars visible tonight
The present staff
The staff present now
The first refers to all the visible stars, the second to only those visible tonight, the third to the entire staff at the moment and the fourth to only those employees who are here.

Determining how an adjective should be understood in the sense of what is included and what excluded is not always simple. It is not that we have a polysemous word acting as an adjective (although that happens) but where the scope of modification starts and stops.

The adjective bad is somewhat ambiguous in this respect. For example:
She felt bad
could imply that she felt unwell or that she felt guilty although this can be disambiguated with the use of the adverb so:
She felt badly
can only mean unhappy or guilty, not unwell.

Classifiers, epithets and punctuation
class

There is some ambiguity in written language whether a word is intended as an adjective (an epithet) or a classifier because:
a senior school teacher
could be interpreted as
a teacher at any type of school who is experienced and older
or
a teacher who happens to work in a senior school
In the former, the word is adjectival and in the latter it is a classifier.

Commas are often optional but required when there is possible ambiguity. For example:
It's a large house plant
is unlikely to be misunderstood as a plant only for use in large houses but to avoid any ambiguity, it can be written as
It's a large, house plant
Compare:
It's a small garden plant
in which there is ambiguity which can be eradicated by punctuating it as
It's a small, garden plant
or
It's a small-garden plant

old and new: inherent and non-inherent meanings
car

The adjective old may be applied to inanimate and animate nouns but when it is applied to animate nouns the meaning will vary depending on how it is used (attributively or predicatively). So, for example:
He is an old friend
will be understood non-inherently as applying to a long-lasting friendship, not to the person but
My friend is old
will be understood as applying to the friend, not the friendship.
Unfortunately the word old has two common antonyms: new and young and they are differently understood depending on the nature of the noun to which they are applied.
So, for example:
She's a new friend
and
All these students are new
will not be seen as applying to the people but to their recent arrival whereas
She's a young friend
or
The students are young
can only be understood as applying to the people directly.
However:
There's a new car in the car park
and
That car in the car park is new
are truly ambiguous and could mean
The car has only recently appeared in the car park
or
The car has recently been manufactured
and only context can disambiguate the meaning.

A further, connected source of ambiguity lies in the fact that some adjectives can apply to a person and to a relationship so, for example, while it is clear that:
She's a new friend
They are old rivals
both apply to the friendship and the rivalry, not the people involved, it is less clear whether the adjectives in
He's a reliable friend
She's a remarkable friend
refer to a reliable / remarkable person or a reliable / remarkable friendship.
Ambiguity can be avoided by using the adjective predicatively because then the assumption will always be that it applies to the person:
My friend is reliable
Her friend is remarkable

Comparative forms
2

The question here is whether the words more and less are acting as adverbs modifying adjectives or as determiners modifying noun phrases. It matters because the meaning changes depending on the grammatical function of the word. In that sense, this straddles the boundary line between lexical and syntactical ambiguity.
Here are three examples:

  1. They provided more accurate figures
    1. = They provided more figures which were as accurate as the old ones
      or
    2. = They provided figures which were more accurate than the old ones
    1. = I want more work from you which is as useful as the work you have done
      or
    2. = I want work from you which is more useful than the work you have done
    1. = She had less work done which was as expensive as the previous work
      or
    2. = She had work done which was not as expensive as the previous work

    The ambiguity arises from the fact that in:
    i.a., ii.a. and iii.a., the words more and less are determiners referring to the noun phrases accurate figures, useful work and expensive work
    but in:
    i.b., ii.b. and iii.b., the words more and less are adverbs modifying the adjectives accurate, useful and expensive

    It is impossible to tell by looking at the sentences what the words more and less are doing grammatically. Rephrasing as above will remove the ambiguity.

    Superlative forms
    Mountaineer, Mountain, Peak, Man, Climbing, Climber

    Compare
    The girl is most intelligent
    and
    The most intelligent girl
    both of which are possibly ambiguous because they can mean either:
    The very intelligent girl
    or
    The girl who is more intelligent than the all the others
    The use of the definite article determiner can disambiguate this because
    The most intelligent girl
    will only be understood in the second sense.
    The key here is not to word class because in all the examples, the word most is an adverb modifying the adjective. However, the word is polysemous because is means very or extremely and it forms the superlative of an adjective expressing the uppermost degree.

    Syntactical ambiguity

    Much of syntactical ambiguity arises from the possibility of, so to speak, throwing a mental switch to decide which line to take.
    Tense forms in English, or most languages, do not have a one-to-one relationship with time. We use, therefore, present and past tenses to talk about the future, past tenses to talk about the present and so on.
    There is a good deal more about this in the guides to time, tense and aspect, linked below, so some examples of the possible ambiguities will be enough here.

    -ing forms

    At first sight, a sentences such as:
    He's driving
    is not ambiguous, especially when it's linked to an image as here.
    However it can mean:

    This is where we encounter a famous Chomskyan concept. Chomsky, to whom there is a guide linked at the end, chose to demonstrate what he meant by deep structure with the example sentence:
    Visiting aunts can be boring
    because that can mean:
    Aunts who visit can be boring
    or
    The activity of paying a visit to aunts can be boring

    It is, in fact a bit of a four-way cheat in our terms here because the ambiguity relies on:

    1. Selecting a transitive verb so that there is manufactured ambiguity concerning subjects and objects. You cannot, for example, construct a similarly ambiguous sentence with verbs like arrive or speak because you get the unambiguous:
      Speaking clocks can be irritating
    2. Selecting a semantically allowable transitive verb. You cannot, for example, construct a similarly ambiguous sentence with verbs like explain or show because you get the unambiguous:
      Showing your anger can be inadvisable
    3. Using the uninflected modal auxiliary verb, can, to disguise the verb-noun concord. You cannot, for example, construct a similarly ambiguous sentence without the modal auxiliary because that produces:
      Visiting aunts bore me
      Visiting aunts bores me
      which contain no ambiguity because the first has a plural noun as the subject and the second has a singular gerund as the subject. We don't need to think about deep structure to disambiguate the sentences, simply leaving out the modal auxiliary verb will do.
    4. Selecting a verb which has a gerund form (a verbal noun) and a participle form which can act as an adjective. You cannot, for example, construct a similarly ambiguous sentence with verbs like wear or repair because neither wearing nor repairing can operate as participle adjectives although the verbs are transitive. We allow:
      Wearing warm clothes can be useful
      Repairing computers needs some care
      but not:
      *These are wearing clothes
      *He is a repairing man

    It is quite difficult to make a parallel sentence to the one Chomsky used although:
    Eating apples can be healthy
    Drinking water can be good
    Cleaning materials may be expensive
    Burning rubbish could be dangerous
    and just possibly
    Climbing plants can be dangerous
    (if you are a field mouse)
    will show the same kind of ambiguity.
    The parlour game is to think of ten more.

    In fairness, this was not the point that Chomsky was making.
    He used ambiguity as a way of revealing the inadequacies of a structuralist approach to grammatical analysis and was not concerned with communicative effect.

    Tense-form ambiguity is a much more important issue for teaching.

    Other non-finite -ing forms

    Misuse of the -ing participle in non-finite clauses often results in what is called a dangling or unattached participle. For example:
    Getting on the bus, John's wallet fell from his pocket
    is semantically and grammatically flawed because it was not the wallet that got on the bus. To avoid this kind of ambiguity, the participle and the main clause verb need to have the same subject. The use of a finite clause solves the issue:
    While he was getting on the bus, John's wallet fell from his pocket
    In this case, little ambiguity is caused because we know that wallets do not, of their own volition, take public transport.

    However, there are times when the rule is not quite so clear cut. For example:
    I saw Mary getting off the bus
    is likely to be interpreted as:
    I saw Mary while she was getting off the bus
    but could mean:
    While I was getting off the bus, I saw Mary
    We need to be more careful here because both the possible subjects are able to take public transport.
    In order to repair the ambiguity, we have to rephrase the sentence as:
    I saw Mary when she was getting off the bus
    or
    I saw Mary when I was getting off the bus

    The rule of attachment to the same subject is often relaxed so we allow:
    Being Friday, the staff left early
    which is not ambiguous because the staff cannot be Friday.
    On the other hand,
    Being optimistic, Mary will be able to do the job
    is ambiguous depending on whether the speaker or Mary is the optimist.
    The ambiguity here is explained a little more (and a little more clearly) below, under semantic ambiguity.

    These sorts of non-finite clauses used to express temporal or causal relationships can give rise to some ambiguity of meaning.
    For example:
    Being in New York, she went to see him
    could mean:
    While she was in New York, she went to see him
    or
    Because she was in New York, she went to see him.

    In all such cases, rephrasing the thought using finite rather than non-finite verb forms solves the problem as can using the right subordinating conjunction as in the examples above.

    Adverbial modification

    It is often difficult to determine which verb an adverb modifies when there are two verbs in the same sentence. For example:
    The people who came quickly got lunch
    has two interpretations depending on which verb is being modified by quickly:

    1. The modified verb phrase is came, in which case we have:
      People who were quick to arrive got lunch
    2. The modification belongs with the verb got, in which case we have:
      The people who came got lunch quickly

    We can rephrase this to remove the ambiguity as we have done here. The key is to put the adverb in the right place.
    It can also be disambiguated by pausing in speech after quickly (and signalling sense 1.) or after came (and signalling sense 2.).
    That is straightforward with middle-position adverbs such as those of manner which are mobile but even easier with adverbs of indefinite frequency as in, e.g.:
    The men who arrived late frequently missed lunch
    vs.
    The men who frequently arrived late missed lunch
    because these adverbs conventionally precede the main verb.

    There are also times when it is not clear whether an adverbial is functioning to modify a verb or its subject or object.
    For example, in:
    His friends at that time were working
    could mean:

    1. His friends were working at that time
      which modifies the verb phrase, or
    2. The friends he had at that time were working
      which modifies the noun phrase

    and unless we know whether the prepositional phrase is modifying the noun or the verb phrase, we cannot arrive at the meaning. This is an example, arguably, of phrase constituent ambiguity, which is considered in much more detail later. The concepts of syntactical and phrase-constituent ambiguity overlap with blurred edges.
    Simple rephrasing (as above) will disambiguate the meanings.

    Finally, there are times when an adverbial can apply to either of two verbs. When verbs form strings in the syntax (i.e., they catenate) some ambiguity sometimes arises in deciding which verb the adverbial is modifying so, for example, in:
    She undertook to do the work straightaway
    it is not apparent whether

    1. the undertaking happened immediately
      in which straightaway is modifying the verb undertake, or
    2. the doing of the work will happen immediately
      in which straightaway modifies to do the work

    The intuitive response from many will be that the adverbial modifies the nearest verb so interpretation b. is probably inferred. We can disambiguate the sentence by moving the adverbial and producing:
    Straightaway, she undertook to do the work
    which signals interpretation a.

    Conjunctions

    Some conjunctions cause ambiguity issues.

    although and while

    Both although and while are subordinating conjunction of concession and occur unambiguously in, for example:
    I like reading in the evening while my husband prefers watching TV
    Although I like reading in the evening, my husband prefers watching TV
    etc.

    A little care is needed, however, because while is also a temporal subordinator so, for example:
    Although it is raining, I'll take a walk
    is unambiguous because although has only one function but
    While it is raining, I'll take a walk
    can mean:
    Although it is raining I'll take a walk
    or
    As long as it is raining I'll take a walk
    It could also mean:
    Because it is raining I'll take a walk
    because while sometimes carries the sense of causality usually signalled by so or because.

    but and although

    There is also scope for ambiguity with the distinction between coordinators and subordinators.
    In coordinated clauses we can omit the subject, providing it is common to both clauses so we get, for example:
    Mary was exhausted but worked on till six
    in which it is clear that Mary is the subject of both clauses.
    We cannot do this with subordination so we do not allow:
    *Although Mary was very tired, worked on till six

    There is, however, a little more to it than that because in a sentence such as:
    He was exhausted but John worked on till six
    it is averred by some that He and John must refer to different people. In other words, He cannot be a cataphoric reference to John in a coordinated sentence. This is somewhat questionable and the sentence is at best ambiguous insofar as He and John could refer to the same person or to different people depending on context and co-text.
    With subordination, on the other hand, cataphoric reference is assumed so in:
    Although he was exhausted, John worked on till six
    it is inevitable that he and John will be assumed to be the same person.

    so and so that: purpose or result?

    The conjunction so also causes problems because it implies both a result and a cause.
    It is resultative in, for example:
    The night was very clear so I could see the ships out to sea
    It is causative in, for example:
    I dug a deep hole so the tree was firmly planted
    However, ambiguity can arise with a sentence such as:
    Someone stole my car so I couldn't get to work
    which means either:

    1. The result of the theft of my car was that I couldn't get to work
      or
    2. Someone stole my car to prevent me getting to work

    The way to disambiguate is to replace so with because when we are referring to result and then we get:
    Because someone had stolen my car I couldn't get to work
    which is unambiguous, or to rephrase the thought as in b.

    The same consideration applies in these examples. It is resultative in:
    The ground was icy so that I was careful how I walked
    in which the care is a result of the ice and so that is acting as a coordinating conjunction.
    It is, however, purposive and a subordinating conjunction in:
    I put salt on the driveway so that the ice would melt

    This means that, e.g.:
    He was standing in the light so that I could see him
    is ambiguous and means either:

    1. The result of his standing in the light was to make him visible
      (coordinating the clauses)
      or
    2. He stood in the light in order to make himself visible
      (subordinating the second clause to the first)

    Again, we have to rephrase to exclude the possibility of ambiguity.

    before

    Temporal conjunctions can also cause ambiguity if handled carelessly. For example:
    I expected he would be happy with the figures before the meeting started
    can be interpreted either as:

    1. Before the meeting started, I expected he would be happy with the figures
      or
    2. That he would be happy with the figures before the meeting started was what I expected

    The ambiguity can be resolved by moving the temporal clause to the initial position as in a.

    if and when

    The conjunctions if and when also cause problems. In, for example:
    When possible, the work should be completed without disturbing the residents
    has two interpretations:

    1. Whenever it is possible, the work should be completed without disturbing the residents
      or
    2. If it is possible, the work should be completed without disturbing the residents

    Resolving the ambiguity simply means being careful to use if when a conditional rather than temporal meaning is intended.

    if and whether

    Consider:
    Tell me if you need any help
    which has two interpretations:

    1. Tell me if you need any help
      as a true conditional in which the imperative depends on the need for help
      or
    2. Tell me whether you need any help
      which is not conditional and simply asks for the speaker to be informed

    Disambiguation again involves using if only in conditional senses.

    because

    Some ambiguity may arise with negative causality so, for example:
    I didn't come because of the chance that she would be there
    may be interpreted either as:

    1. The reason I didn't come was because there was a chance she would be there
      or
    2. The reason I came was not that there was a chance that she would be there

    Only context and intonation (stressing because) will disambiguate the meaning unless we rephrase the whole meaning as:
    There was a chance she would be there so I didn't come
    and
    That there was a chance she would be there was not the reason I came.
    This is also considered below when we come to the ambiguity that negative sentences can evince.

    to and in order to

    The word to is sometimes just an abbreviation of in order to.
    This can create some ambiguity.
    Compare for example:

    In the first case, we have a to-infinitive doing its usual catenative job referring to a prospective event.
    In the second case, however, to is an abbreviation of in order to and is not catenative.
    Here's a slightly different example:

    is ambiguous because it means either:

    and only rephrasing such as above can disambiguate the sentence.

    Clause constituents

    This is a major area of ambiguity and the final one to tackle under syntactic ambiguity.
    There is a dedicated guide to disentangling clause constituents on this site, linked below, so here we will rely on a few examples of the sorts of ambiguity that can arise.
    Here are the examples:

    Instrumental phrases

    Many case-grammar languages have a way of marking instrumental case but English doesn't, preferring to rely on prepositional phrases. Unfortunately, prepositions themselves are polysemous. The preposition with carries the meaning of an instrument as in:
    I cut down the tree with an axe
    and of accompaniment as in:
    The man in the corner with the dog.
    This causes problems.

    For example:
    Anne hit the intruder with a chair
    is probably not ambiguous at all (but it is conceivable that the intruder was carrying a chair).
    Anne shot the intruder with a knife
    is also unambiguous because you can't shoot someone with a knife so the only interpretation is that the intruder carried the knife.
    However,
    Anne hit the intruder with a gun
    is truly ambiguous because it can be interpreted as either:

    1. Anne used a gun to hit the intruder
      or
    2. Anne hit the intruder who was carrying a gun

    So rephrasing is necessary to make the sense clear.

    Prepositional phrases as modifiers of nouns or verbs

    Take:
    I shouted to the man by the river
    which has two interpretations:

    1. By the river I shouted to the man
      or
      It was by the river that I shouted to the man
    2. I shouted to the man who was by the river
      or
      It was the man by the river that I shouted to

    It depends on whether we consider by the river to be an independent phrase or one which is attached to the noun.
    The subject of the sentence is clear: it is I.
    The object, however, can either be:

    river

    The adverbial phrase which modifies the verb is then absent (if a. is the object) or is by the river if b. is the object.
    In other words, we have to decide whether the shouting happened by the river or not.
    We can use a diagram to make it clear:

    In the first case the verb phrase in blue has the blue adverbial modifying it with the verb's object in red. The phrase by the river is independent and can be moved to the beginning to get:
    By the river I shouted to the man
    In the second case the verb phrase is unmodified and the object is in red but by the river is not an independent phrase because we cannot move it to the beginning and retain the same sense.

    Here are some more examples taken from various guides on this site for you to untangle: