对从事开采冲击地压煤层有关人员，必须进行（）基本知识教育，熟悉冲击地压发生的（）等基础知识以及需要采取的防治措施。
参考答案：防治冲击地压；原因、条件、前兆
用所给词的适当形式填空。
l. Don't play while _____ (eat).
2. It's_____ (usual) for a 7-year-old boy to work out the difficult problem.
3.Who jumps_____ (high)in your class?
4. Why don't you try_____ (ride) a bike to go to school?
5. Keep_____ (work) hard until you make it.
I wish for a family____________my parents are treating me like a friend.
A．why
B．which
C．that
D．where
