一些有关英语的问题,
1.doubt后面的宾语从句什么时候接that,whether.
2._____iunderstandwhatyousay,icannotagreewithyou.
A.whenB.while
正确答案选B,为什么呢
3.thescientistsareconfusedasto___theyshouldcalltheanimal,whichlookshalf-animal.
A.thatB.whyC.whoD.what
正确选D,为什么?