Robert often asks us his Chinese so his Chinese is much better than before.　A. help him B

问题补充：

Robert often asks us his Chinese, so his Chinese is much better than before.

A. help him

B. to help him with

C. to help with

D. helps him with

答案：

A. help him

(答案→)B. to help him with

C. to help with

D. helps him with

解析：不定式可以用作宾语补足语。后面可以接不定式作宾语补足语的动词有 ：ask， teach， expect，tell， allow等。