When the teacher comes we all stop and do our homework?A. talkingB. to talkC. talkD. tal

问题补充：

When the teacher comes, we all stop and do our homework?

A. talking

B. to talk

C. talk

D. talks

答案：

(答案→)A. talking

B. to talk

C. talk

D. talks

解析：老师进来了，按照常理应该是停止讲话了，去做作业了，stop doing表示停止，

而stop to do 表示停下来去做，根据题意选择前者，故选A,talking。