if more young people voted, politicians (would pay more attention to what young people thought.)
A.as it is
B.(would pay more attention to what young people think.)
Correct answer is B. shoulnd’t “think” be “thought” ?
In the predawn crispness of a September morning, the conjunction of Mars and Venus thrilled the amatuer astronomer ( like on the first occasion he had seen it.)
A.as it is
B. (like on the first occasion he had seen it)
C. (as when he was thrilled the first time.)
D (like the thrill when he first saw it)
E (as it had the first time he saw it )
Correct answer is E, but i have no idea why E is correct and others are incorrect ??? i need clear explanation 
(During the recent) earthquake, all of Luissa’s pictures (fell off) the mental, (having left) many of (them) shattered beyond repair. (No error)
Error is “having left”. WHY ???
Neither Susan nor Jacob (likes) (to relax) and (watch) the grass ( grows). No error
Error is “grows”. ??
thank you guys for helping me out 
I guess for the first question, it’s a hypothetical, so you have to supply a present verb there.
For the second question, the subject of the sentence is “the conjunction of Mars and Venus,” and E is the one that uses a subject in its clause.
Who left the pictures shattered beyond repair? You need a subject from the previous clause to be the doer of that participle, and interpreting that last part of the sentence, the earthquake should be the one doing the shattering (the earthquake leaves them shattered beyond repair). However, earthquake is not the subject because it is in the subordinate clause at the beginning. The subject of the sentence is actually the pictures.
You are watching something grow. Just say the sentence out loud and you’ll get it. You never say that “you want to watch the grass grows.”
For the first question, as the above poster said, since its a hypothetical question (if), then we ignore the tense change.
For the second question, it directly references “the conjunction of Mars and Venus” so that means the answer had to reference it directly after as well. That gets rid of A, B, C, and D (because only choice E mentions “it” which is grammatically correct in referencing “the conjunction of Mars and Venus”). No other choice references “the conjunction” as a pronoun before referencing the astronomer seeing it, which is incorrect. If you reference a subject previously in a sentence, you must use a pronoun right after; these questions are extremely common on the SAT.
The next question follows a tense change (present tense). It begins with “During” and “having left” is wrong since that’s past tense. It should be “leaving” instead.
Lastly, like the above poster said saying “to watch the grass grows” is just wrong when said out loud, lol. It should be “grow”.
Thank yo guys, but i still dont understand the third one "having left vs leaving " i need comprehensive explanation )
quote earthquake, all of Luissa’s pictures (fell off) the mental, (having left) many of (them) shattered beyond repair. (No error)
Error is “having left”. WHY ???
[/quote]
“Having [pp]” means the action occurred before the next past action: “Having failed all my classes, I was kicked out of school.” (See how the failing happens before the expulsion?)
“Leaving” puts the two actions at the same time reference: “Leaving my office, I bumped into The Ultimate Warrior.” (See how the two events happen simultaneously?)
In the initial sentence, the shattering can’t have occurred before the falling, so “having left” breaks the time logic of the sentence.
Thank you so much marvin100.
My pleasure @NOTFLIPPANT. Best of luck to you!