They are considering they should do the experiment .A. weatherB. thatC. whetherD. what

问题补充：

They are considering they should do the experiment .

A. weather

B. that

C. whether

D. what

答案：

A. weather

B. that

(答案→)C. whether

D. what

解析：考查连词，句意：他们正在考虑他们是否应该做实验。所以用whether是否。