Please correct my answers if they are wrong. Thanks.
1. ) If anybody here has a cell phone (they/ he or she) should turn it off. ANSWER: he or she
2. ) Many high schools now require (its/their) students to take a computer class. ANSWER: its
3. ) Each of these actresses who auditioned believes (she/they) should be chosen for the role. ANSWER: they
4. ) Students complain that (they/ the maintenance crew) keep(s) the library too hot. ANSWER: they
5. ) While Eric was adding sugar to his coffee, he spilled (it/the sugar) all over the table. ANSWER: it
6. ) Someone offered to show me a copy of next week’s history test, but I said that I didn’t believe in (this/ cheating). ANSWER: cheating
7. ) If high school juniors and seniors take a special class to prepare them for SAT’s (you will/they will) probably have a higher score. ANSWER: they will
8. ) I know spring is really here when (I / you) see neighborhood kids playing baseball. ANSWER: you
9. ) If you want to advance in this company, (we/ you) must be willing to work overtime. ANSWER: you
Please help.

3) she –(the word “each” is your clue)
I –(subject agreement rule)
4) the maintenance crew –(clarifies the subject of the sentence)
1 correct
2 wrong (schools is plural and needs plural pronoun)
3 wrong
4 wrong (they would refer to the students, but students do not control heat)
5 wrong (can’t tell if the sugar or the coffee spilled if you use “it”)
6 correct
7 correct
8 wrong
9 correct
2) their
I-because you are using I at the beginning, you should continue to use it
3) she
4) maintenance crew-why would the students control the temperature of the school?
5) the sugar-you talk about 2 spillable things so you need to clarify which one has been spilt
hope this helps