This document discusses rewrite systems and methods for parsing sentences. It provides examples of parse trees constructed using bottom-up and top-down methods. Bottom-up trees are often easier for beginners, starting with individual words and building up the tree structure. Top-down trees are quicker for experts, who start with the sentence node and fill in constituent parts working downwards. Various grammatical components are also defined, such as noun phrases, verb phrases, and prepositional phrases.

1. REWRITE SYSTEMS
Dr.VMS

2. THE BOY SOLVED THE PROBLEM

3. PS RULES

4. NP - VP - PP

5. TIM THOUGHT THAT KATE BELIEVED THE
STORY

6. PS DESCRIPTION

7. TIM THOUGHT THAT KATE BELIEVED THAT GREG
IS A LIAR

8. PS DESCRIPTION

9. REWRITE METHODS
 AP
 NP
 VP
 PP
 DP
 TP
 CP

10. DP

11. NP

12. TP

13. TP

17. BOTTOM-UP TREES
 This method for tree drawing often works
best for beginners. Here are some (hopefully
helpful) steps to go through when drawing
trees.
 D A A N V D N
 The very small boy kissed the platypus

18. BOTTOM-UP TREES

19. THE TOP-DOWN METHOD OF TREES
 Most professional syntacticians use a slightly
quicker means of drawing trees. Once you are
practiced at identifying tree structures, you will
probably want to use this technique. But be
warned, sometimes this technique can lead you
astray if you are not careful
 This method starts out the same way as the other:
write out the sentence and identify the parts of
speech.
 D A A N V D N
 The very small boy kissed the platypus.
 Next draw the S node at the top of the tree, with
the subject NP and VP underneath:

20. TOP-DOWN

21. TOP-DOWN

22. TOP-DOWN

23. AP-NP

24. AMBIGUITY

25. PS RULES