Shelooksverybusy.Iwanttohelpher,butIdon’tknow

問題詳情：

She looks very busy. I want to help her, but I don’t know_____.

A. how to do   B. what to do it   C. what to do    D. why to do

【回答】

C

知識點：非謂語動詞

題型：選擇題