My mother often tells me my classmates when they need.A. helpB. to helpC. helpingD. helps

问题补充：

My mother often tells me my classmates when they need.

A. help

B. to help

C. helping

D. helps

答案：

A. help

(答案→)B. to help

C. helping

D. helps

解析：考查短语：tell sb to do 告诉某人做某事，句意：我的母亲经常告诉我帮助我的同学当他们需要的时候。故选B。