They urged that the library open during the vacation.A. must be keptB. is keptC. would be

问题补充：

They urged that the library open during the vacation.

A. must be kept

B. is kept

C. would be kept

D. be kept

答案：

A. must be kept

B. is kept

C. would be kept

(答案→)D. be kept

解析：考察虚拟语气。Urge后面的宾语从句使用should+动词原形；should可以省略。故D正确。