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

Question

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?)

Answer 1

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.