用适当的连词填空（速度回答,）
1.The performance had begun___they arrived at the theater.
2.They kept on working___it was very late.
3.You may fail in the exam___you don't do your best.
4.Use your head,__you will have an idea.
5.She has to leave right away___sha doesn't want to.
6.I did not hear___he said at the meeting.
7.He still remembered the place___he had worked for years.
8.The doctor___treated the old man is from Beijing.
9.I've told you___treated you may___go there___stay here.
10.Let's start early___we won't be late for the meeting.