1.Later in this chapter cases will be introduced to readers ___consumer complants have resulted in changes in the low.
A where B when C who D which
2.While paying for the gas,Mary's mother told the seller about the nice night ___she had spent at the Welcome Inn.
A in which B when C on which D that
3.Early in the 1990s no one had any idea that J.K Rowling had come up with The sorty of Harry potter, ___later became a best seller.
4.He has entertained hopes of being admitted to a sight of the wondeeful valley,___beauty he has heard much.
A who B of whose C whose D from which
5.We hope in the future Irap will be a peaceful and powerful country,___contribute to the development of the Persion Gulf region.
A that will B one that will C which D one
6.___is often the case,nobody came up with the right answer except the moniter.
Awhich B when C what D as
7.Please learn to keep your private information safe,___is the key to protecting yourself.
A it B which C why D that
8 Is this the reason ___at the meeting for his carelessness in his work?
A he explained B what he explained C how he explained D why he explained
9.The place ___the bridge is supposed to be built should be___the cross-river traffic is the heaviest.
A which,where B at which,which C at which,where Dwhich,in which
10I'd like to know the reason___you're so late.
A that B why C for D because
以上各题要求详细的解释，另外弟8题和第10题看上去很像，但第8题选A,第10题选B,reason后面为什么加了不同引导词？