II. 单项选择
21. It is known that water is not _____ endless resource, nor _____ that can be made once more.
A. the; 不填 B. an; one C. an; that D. 不填；one
22. I’m not sure whether I will have anything else to do tomorrow. ____,I will try every possible means to come to the party.
A. Even though B. Anyhow C. If so D. Instead
23. It is required that the students ______ mobile phones in their school, so seldom ____ them using one.
A. not use; will you see B. should not use; you will see
C. don’t use; will you see D. not use; you will see
