She doesn’t knowA. what she can do itB. what to do itC. how to doD. how to do it

问题补充：

She doesn’t know．

A. what she can do it

B. what to do it

C. how to do

D. how to do it

答案：

A. what she can do it

B. what to do it

C. how to do

(答案→)D. how to do it

解析：句意：她不知道该如何做这件事？how to do it为how加不定式构成的结构做宾语，或者用what to do做宾语，表示该做什么；故选D。