－I’d like to help the homeless people in the earthquake. －You join a volunteer group. A.

问题补充：

－I’d like to help the homeless people in the earthquake.

－You join a volunteer group.

A. must

B. need

C. can

D. couldn’t

答案：

A. must

B. need

(答案→)C. can

D. couldn’t

解析：句意：-我想去帮助地震中无家可归的人。-你可以加入志愿者团体。A must必须B. need 需要在疑问句和否定句中做情态动词C. can能，会，可以D. couldn’t不能。根据句意故选C