.I recommended an English-English dictionary which I thought would be of great help to h

问题补充：

.I recommended an English-English dictionary, which I thought would be of great help to her studies.

A. buying

B. bought

C. to buy

D. he bought

答案：

(答案→)A. buying

B. bought

C. to buy

D. he bought

解析：动词用法题。“建议”recommend doing sth; recommend sb to do sth; recommend that sb (should )do sth 。句意：我建议买一本英语词典我认为会对她的学习有很大帮助。