Q set 3 ("Many people think of the desert...")

Passage I (Many people think of the desert...)

1. C - We want the choice that suggests negating the opinion. Disposes is close, but the meaning is too strong. 

2. J - Past tense

3. B - The sentence begins with "Situated in Southern California..." This is a phrase that needs to modify whatever comes right after it, so what comes after needs to be something that is situated in southern Cal. The only possibility is valley, which makes the right answer B. When the thing after the comma can't be modified by the phrase, we call it a dangling modifier. 

4. H - It completes the comparison "as many as."

5. B - Has (present perfect tense) suggests the lake is currently in the state of drying up.

6. J - It's redundant (we already have "Called"; that's often the reason for omitting the portion).

7. A - Just simple past tense

8. H

9. C

10. H - This is both stylistically best (it flows) and grammatically correct (the other options have either verb problems or, with choice F, a dangling modifier. 

11. A

12. J

13. A

14. G - The phrase "extending . . . October" is non-essential to the sentence, meaning it's parenthetical. You can take it out and it doesn't change the meaning and focus of the sentence. In that case you want commas around it. If removing the phrase alters the sentence's meaning, then leave out the commas.

15. C - The other choices add unnecessary wording.