Can you please check these sentences for me? Thank you. I'm unsure about using phrasal verbs in a context.

1) She is thinking of dropping out of school. She doesn't know if she'll be able to deal with her problem by herself.
2)She doesn't like talking through her school difficulties with somebody else. She knows she can always depend on her sister for help.
3) Her sister is very self-confident and she always works out her problems herself (also: by herself, on her own).
4)She has just found out that she has an English test tomorrow.
5) I think my boyfriend is going out with another gir. I think you should talk to him to find out if it's true.
In that case, you should dump him(break up with him?).
6) I think you should let your sister wear your clothes but only when you are not there. I think you should try to get her out the habit of wearing your clothes. (She shouldn't let it become a habit?).
7)I think you should hide your CDs from her, so that she can't borrow them any longer.
8)I think you should tell your parents about your bad mark in Maths. Lying (to parents) is wrong. You'll lose the trust of your parents, then. You should promise them you'll do better next time (also: to do better next time?)

1 and 2 are OK.

3 needs a comma where the two independent clauses come together. Yes, all three choices at the end of the sentence are fine.

4 just needs a spell check. Which word? Do you see it?

5 also needs a spell check, and yes, your choice at the end of the 2nd sentence is fine.

6 needs a comma after "clothes."

7 is OK.

8 is OK.

1) The sentences are grammatically correct. The use of phrasal verbs in these sentences is appropriate. "Dropping out of school" means to leave school before completing the program. "Deal with" means to handle or manage a problem.

2) The sentences are grammatically correct. The use of phrasal verbs in these sentences is appropriate as well. "Talking through" means discussing or addressing something. "Depend on" means relying on someone for support or assistance.

3) The sentences are grammatically correct. The use of different phrases ("herself," "by herself," "on her own") is interchangeable and conveys the same meaning. All of these phrases indicate that she is independent and capable of solving her own problems.

4) The sentence is grammatically correct. "Found out" means to become aware or discover something.

5) The sentences are grammatically correct. The use of phrasal verbs is appropriate. "Going out with" means dating or being in a relationship with someone. "Talk to him" means to have a conversation with him. "Find out" means to obtain information or discover the truth.

Regarding the phrase, "dump him" means to break up with someone.

6) The sentences are grammatically correct. The use of phrasal verbs is appropriate. "Let your sister wear your clothes" means permitting or allowing your sister to wear your clothes. "Get her out of the habit" means to help her stop or break the habit of wearing your clothes.

Regarding the alternative phrase, "She shouldn't let it become a habit" has the same meaning, indicating that she should not allow the behavior to become a regular occurrence.

7) The sentence is grammatically correct. The use of phrasal verbs is appropriate. "Hide your CDs" means to keep your CDs out of sight or store them in a place where she cannot find them. "Borrow them any longer" means that she will no longer be able to borrow them.

8) The sentences are grammatically correct. The use of phrasal verbs is appropriate. "Tell your parents" means to inform or communicate with your parents about something. "Lose the trust" means that by lying, you will no longer have their trust. "Do better next time" means to improve or achieve better results in the future.

Regarding the alternative phrase, "to do better next time" has the same meaning, indicating that you should promise to improve your performance in the next opportunity.