Question

They learned it all by themselves. That is to say nobody told them ________ .

A．what to do it

B．how to do it

C．where to do

D．when to do

Answer 1

B

解析試題分析：句意：他們是自學的這些技能。也就是說沒有人告訴他們該如何去做這些事。本句考查特殊疑問詞+to do做賓語；A項中it多余；C和D項少了it；結合句意可知，B項符合要求；故選B。
考點：考查特殊疑問詞+不定式。