Phrase Structure Rules $($PSRs$)$

S $$ NP VP $($PPloc$)($PPtime$)$

NP $($Det$)($AP$)$ N $($PP$)($PP$)$

NP $$ Name

NP $$ Pro

VP $($Qual$)($Aux$1)($Aux$2)($Aux$3)$ V $($NP$)($AP$)($PP$)($PP$)$

AP $($Deg$)$ A $($PP$)$

PP $($Deg$)$ P $($NP$)($PP$)$

Part A$.$ The PSRs above successfully account for the sentences below.

$(1)$ The letter to the editor is very unbelievable.

$(2)*$It to the editor is very unbelievable.

$(3)$ These pieces of wood are rotting.

$(4)*$They of wood are rotting.

Show this by doing two things. In the first box below, draw a sentence tree for $(1),$ to show that the PSRs can

generate it$.$ Your tree structure must show all syntactic categories $($phrasal$,$ lexical, non$-$lexical$)$ as nodes on the

tree, and it should show the constituent structure that the PSRs assign. Also, the trees must follow the rules for

well$-$formed trees $($see the Syntax lecture slides if this is unclear$).$ In the second box on the right, explain why

the rules cannot generate $(2)$ and $(4).$ Use complete sentences and make explicit reference to the syntactic

categories of these sentences and the PSRs$.$

Tree for $(1)$

The letter to the editor is very unbelievable

Explanation of ungrammaticality of $(2),(4)$

$1$ Acknowledgement: this problem is based on a similar problem developed originally by Sandra Chung.

Part B$.$ Sentence $(5)$ below is ambiguous, but $(6)$ is unambiguous. $(5)$ can have a $$editor as addressee$$

meaning, where I read the letter that was addressed to the editor, but the editor may or may not be present. $(5)$

can also has a $$editor as audience member$$ meaning, where I read the letter $($not necessarily addressed to the

editor$)$ and the editor was part of my audience. $(6)$ only has one meaning, where I read something, and the

editor was present as part of my audience.

$(5)$ I read the letter to the editor.

$(6)$ I read it to the editor.

It turns out that our current PSRs actually account for these facts as a consequence of the sentence trees it

generates. Your task is to illustrate this by generated two legal sentence trees for $(5),$ but only one for $(6),$ in the

boxes provided below. Again, show all the relevant information and follow the rules for well$-$formed tree

construction. Hint: a guiding assumption for relating sentence trees to meanings is that the PP complement $$to

the editor$$ acts as a modifier of the head that it is a sister to$.$ Finally, you are to explain in a few sentences why

the PSRs predict that $(6)$ only has one meaning $($resulting from one tree$),$ while $(5)$ has two meanings $($resulting

from two trees$).$ Again, make direct reference to the sentence patterns and the PSRs$.$

Tree for meaning $1$ of $(5)$

I read the letter to the editor

Tree for meaning $2$ of $(5)$

I read the letter to the editor

Tree for $(6)$

I read it to the editor

Explanation for unambiguous $(6),(8$ points$)$