Question

The old lady did not know ___________when the house caught fire.

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

Answer 1

B

試題分析：句意：當房子著火的時候，那位女士不知道做什么。因為do是及物動詞，所以需要賓語，how不能作賓語；故排除A；如果用疑問詞what，它可以作do的賓語，就沒有必要用it，故排除D；故選。