Homework 5: More Phrase Structure & Ambiguity



1. Ambiguity Strikes Back

The following sentence has a number of different possible interpretations:

Jack decided that he would drink the liquid in the vial in the dungeon.

How many different structures/interpretations can you find? What is the structure associated with each meaning?

You will need to use the following two modifier rules for attaching the PPs.



For the embedded clause, you can treat the word "would" as an Auxiliary (some of you know this as a 'helping verb'), and you can add the rule



Tip: Do not try this question by simply looking at the sentence and trying to think of as many possible meanings as you can. It will be more effective if you approach this question by thinking about possible structures that you can assign to the sentence, and thinking in particular about which positions the two PP modifiers can attach to. Once you have figured out possible structures, you can examine the structures to see what each of them means. (Note: Some of them may not make "real-world" sense, but are still legitimate interpretations based on the structure of the sentence.

Ex: Sarah jumped in the coin --> "Sarah jumped and her jumping happened in the coin." Nonsensical, but a reasonable interpretation, given the VP --> VP PP phrase structure rule.)

Tip 2: When explaining the meanings, be careful to make sure that your explanation is not itself ambiguous!

2. Arguments vs. Modifiers

The ultimate goal of this exercise is to draw syntactic trees for the sentences in (a-f). However, in order to do this, you will need to know whether the phrases in brackets are arguments or modifiers of the verb. If they are arguments, then they will attach to the tree inside the (smallest) VP. If they are modifiers, then they attach above VP, forming a larger VP ... as in the many examples we have seen in class.

In order to determine whether the bracketed phrases are arguments or modifiers, you will need to use the "do so" test that we used in class. Recall that "do so" can be used to stand in for a VP: therefore "do so" must replace all of the arguments of a verb when it is used, but only optionally stands in for modifiers. For example, in the two sentences below, the fact that the PP "on Thursday" can be used with do so indicates that it is a modifier; the fact that the PP "on the shelf" cannot be used with do so indicates that it is an argument of the verb put.

The cat meowed [on Tuesday] and the dog did so [on Thursday]
*The boy put the book [on the table] and the girl did so [on the shelf]


A guide to using the "do so" test.

For each of the sentences below:
(a) use the "do so" test to show whether the bracketed phrase is an argument or a modifier -- you should include in your answer the test sentence(s) that you created.
(b) draw a syntactic tree for the sentence, reflecting the conclusions drawn from your tests.

  1. Jareth likes [amusing plots].
  2. Angel fought [with Buffy].
  3. Jack composed a song [for her].
  4. A dwarf ran [past the wicked queen].
  5. Clever pigs snorted [after the performance].
  6. Sarah waltzed [down the path].


You should be able to draw trees for all of these sentences using syntactic rules/tree fragments that you have already seen.