1.In face of the fire,he hesitated for a while,______whether

1.In face of the fire,he hesitated for a while,______whether he should rush into the burning house.
A.to think B.thought C.thinking D.and thought
2.We______have class in the last week of February,but I'll let you know for sure as the time approaches.
A.should't B.mustn't C.may not D.needn't
3.MR.Smith didn't understand______made his son so upset this morning.
A.what was it B.why it was this C.how that was D.what it was that
4.The name originated from the days______this house belonged to the local policeman.
A.which B.when C.that D.what
5.______harder,you would have passed this exam.
A.if you have worked B.if you worked C.were you to work D.had you worked