It is vital that every piece of equipment before the experiment.
A. is checked
B. will be checked
C. be checked
D. must be checked
网友回答
A. is checked
B. will be checked
(答案→)C. be checked
D. must be checked
解析：本题考查虚拟语气。句型Itisvitalthat中，从句中谓语动词用should 加 动词原形，should通常可以省略。