The boy finally was beginning his mistakes.A. that he sawB. for him to seeC. seeingD. to

问题补充：

The boy finally was beginning his mistakes.

A. that he saw

B. for him to see

C. seeing

D. to see

答案：

A. that he saw

B. for him to see

C. seeing

(答案→)D. to see

解析：start, begin 等词的进行时,不用动名词做宾语,所以不选C. A B两项的语法结构不对.