The father often buys his son English learning materials, at encouraging him to learn English.
A. aim
B. aimed
C. to aim
D. aiming
网友回答
A. aim
(答案→)B. aimed
C. to aim
D. aiming
解析：考查过去分词做状语，be aimed at doing…，旨在做…,这句话前面是完整的句子，后面是状语，用过去分词做状语，句意：爸爸经常给儿子买英语学习材料，目的是鼓励他学习英语。选B。