英语名词从句选择题

英语名词从句选择题
1.I read about it in some book or ther,does it matter____it was?
A.where B.that C.how D.which
2.What the doctor really doubts is _____my mother will recover from the serious disease soon.
A.when B.how C.whether D.if
3.Perseverance is a kind of quality and that's _____it takes to do anything well.
A.what B.that C.which D.why
4.The other day,my brother drove his car down the street at____ I thought was a dangerous speed.
A.as B.which C.what D.that
5.You are saying that everyone should be equal,and this is ____I disagree.
A.why B.where C.what D.how
Pleas give me key,and the reason.
Thanks very much