Sub-Verb Matching with "of"

[MingyiB154]

Hi - I am confused with the following two examples (from correct answer choices):

OG 2018 Q733: Answer is B "... is in the middle of the belt of asteroids that orbit the Sun between Mars and Jupiter."

vs.

OG 2018 Q739: Answer is A "a thick layer of needles protects the buds from which new growth proceeds"

Why does the verb in the 1st sentence use plural form, while that in the 2nd sentence use singular form?

Thanks!

[Sage Pearce-Higgins]

Good comparison; this shows something interesting about sentence structure and modifiers. The use of the singular or plural form depends on the subject (i.e. what's doing the verb). In the first case, the subject is 'asteroids', i.e. they orbit; in the second case, the subject is 'a thick layer'.

You might have noticed that the first example has the word 'that' in it. This indicates a noun modifier (think "NOUN that"), i.e. a phrase that gives extra information about a noun, for example in the sentence 'This is the dog that bit me.' the phrase 'that bit me' gives information about the dog. Now, you might be thinking 'is it the belt that orbits the Sun, or is it the asteroids? I.e. could we say 'the belt of asteroids that orbits', with the modifier 'that orbits' skipping out the phrase 'of asteroids' and modifying 'belt'?', and that's a good question. However, a quick scan of the answer choices shows that GMAT isn't testing you on this difference. My instinct would be that this is too subtle a split for them to be concerned with.

On the simpler side, when you've got a simple subject-verb relationship, the word 'of' indicates a modifier (i.e. something that you can leave out temporarily). For example, which of the following sentences is the correct one?
a) The bowl of apples is on the table.
b) The bowl of apples are on the table.
However, the word 'that' indicates a modifier that usually refers to the NOUN right before it. Which of these is correct?
c) I saw an exhibition of photographs that were taken by David Hurn.
d) I saw an exhibition of photographs that was taken by David Hurn.

[MingyiB154]

Thanks for the quick reply Sage! This is super helpful.

For example, which of the following sentences is the correct one?
a) The bowl of apples is on the table. <- This one!
b) The bowl of apples are on the table.
However, the word 'that' indicates a modifier that usually refers to the NOUN right before it. Which of these is correct?
c) I saw an exhibition of photographs that were taken by David Hurn. <- This one!
d) I saw an exhibition of photographs that was taken by David Hurn.

[Sage Pearce-Higgins]

You got it!