These days students in some schools not to use mobile phones. A. askB. askedC. are askedD

问题补充：

These days students in some schools not to use mobile phones.

A. ask

B. asked

C. are asked

D. were asked

答案：

A. ask

B. asked

(答案→)C. are asked

D. were asked

解析：被动语态。主语students是动作的承受者，所以用被动语态；根据these days可知用一般现在时。