It is required that the studentsmobile phones in their school so seldomthem using one.A.

问题补充：

It is required that the studentsmobile phones in their school, so seldomthem using one.

A. should not use; you will see

B. don’t use; will you see

C. not use; will you see

D. not use; you will see

答案：

A. should not use; you will see

B. don’t use; will you see

(答案→)C. not use; will you see

D. not use; you will see

解析：考查虚拟语气及倒装结构。Require要求，从句用should + v原形，should可以省略；否定词seldom放在句首，主句的主语与谓语发生倒装。选C。