1

معالجة اللغات الطبيعية رابعة حاسب محاضرة (١٠)

دكتور/ أحمد الحربى

Questions

1- For each sentence below, draw a parse tree that is consistent with

the following grammar and corresponds to the semantically correct

interpretation of the sentence.

S NP VP

VP verb

VP verb NP

VP verb NP NP

VP verb NP PP

VP verb NP PP PP

PP prep NP

NP NP1

NP NP1 PP

NP1 art noun

NP1 adj noun

NP1 art adj noun

NP1 noun

2

(a) The small boy threw his hat into the tree.

(b) Mary gave George of the Jungle a book.

(c) The man on the moon drank water from Earth from a cup.

2- Consider the sentence:

Hot air balloons have been floating over the mountains in Utah for the balloon

festival.

Assume the correct parse is:

(s (np (np1 (adj hot) (noun air)) (noun balloons))

(vp (aux have) (aux been) (verb floating)

(pp (prep over) (np (art the) (noun mountains)

(pp (prep in) (np (noun utah)))))

(pp (prep for) (np (art the) (np2 (noun balloon) (noun festival))))))

Suppose your parser generates the following parse:

(s (np (adj hot) (np2 (noun air) (noun balloons)))

(vp (aux have) (verb been)

(np (gerund floating))

(pp (prep over) (np (art the) (noun mountains)))

(pp (prep in) (np (noun utah)

(pp (prep for)

(np (art the)

(np2 (noun balloon) (noun festival))))))))

3

Compute the recall and precision accuracy of your parser for this sentence. (Do not

count part-of-speech tags when measuring accuracy.)