对石油钻机绞车的所有水气管线、阀门、压力表的性能，（）必须检查一次，
A.每月
B.每季度
C.每年
D.每打1口井
参考答案：D
用所给动词的适当形式填空。
1. He _______ (not go) camping next week because he _______ (study) for exams.
2. My cousin _______ (finish) school next month.
3. _______ you _______ (go) to the zoo tomorrow?
4. What _______ you _______ (do) these days? I _______ (learn) English.
5. _______ he _______ (play) computer games at the moment?
6. _______ your brother _______ (come) tonight?
7. Look! The monkey _______ (eat) a banana.
8. There _______ (be) a man in the office.
9. The shop _______ (open) at 8:00 a.m.
10. _______ (be) there any toys in the shop?
