His mother found him ________ inventing different kinds of things A,being good at
问题描述：
His mother found him ________ inventing different kinds of things A,being good at
B,to be well in C,good with D,good at
答
A find sb后只跟doing,done ,（to be） adj.不跟不定式和动词原形.这里选项A是be动词的doing形式,就是being,be good at 是固定用法