.The global warming is going to be a big problem and many people are wondering we can do

问题补充：

.

The global warming is going to be a big problem and many people are wondering we can do with it.

A. if

B. how

C. that

D. what

答案：

A. if

B. how

C. that

(答案→)D. what

解析：可联系答.案.网客服索取。