1. Don't bring friends from other schools, or  the teachers will ask them to leave. (改为同义句)
    _____ _____ bring friends from other  schools, the teachers will ask them to leave.
2. I will play volleyball if it is fine tomorrow. (对划线部分提问)
    _____ _____ you _____ if it is fine  tomorrow?
3. The students stood there and didn't know  what they should do next. (改为同义句)
    The students stood there and didn't know_____ _____ _____ next.
4. They are going to do more practice. They will  win the match. (改为含有if条件句的复合句) 
    They_____more practice, they _____ _____ the match.
5. If you study hard,  you'll catch up with  others. (改为并列句)
    _____ _____, or you'll fall behind others.