–How soon can you finish the work? We can finish it in 20 minutes if we have one more p

问题补充：

–How soon can you finish the work?

--We can finish it in 20 minutes if we have one more person us.

A. to help

B. helps

C. helped

D. helping

答案：

(答案→)A. to help

B. helps

C. helped

D. helping

解析：表示目的用动词不定式to do，故本题选A。