Tom’s mother kept telling him that he should work harder but didn’t help.A. heB. whichC.

问题补充：

Tom’s mother kept telling him that he should work harder, but didn’t help.

A. he

B. which

C. she

D. it

答案：

A. he

B. which

C. she

D. it

解析：句意：Tom的妈妈总是告诉他应该更加努力学习，但是这毫无帮助。后半句中的空代表的是“妈妈总是告诉他应该更加努力学习”这件事，所以用it代替。故选D。