Question

The experts present at the conference all insisted that greenhouse gas emission        be reduced from now on．  

A．must

B．will

C．/

D．can

Answer 1

C

试题分析：句意：出席会议的专家都坚持温室气体排放从现在起要减少。动词insist做为“坚持要求”的时候，后面的宾语从句，用虚拟语气，谓语是should do，should可以省略，所以选C。