几道英语单项选择问题

几道英语单项选择问题
1.This is the small house ____ I lived ten years ago.
A.that B.which C.of which D.where
D (为什么不能选A,A和D什么区别分别用于哪几种情况,或者有什么窍门)
2.A new school ____ over there in two years.
A.may build B.may be built C.will build D.was built
B (后面是in + 一段时间,应该用将来时吧,为什么选B,如果C改成will be built是不是就可以选的)
3.The reason ____ he didn't come to school yesterday is ____ his mother was ill.
A.why;because B.why;that C.that;because D.that;that
B (为什么不能选C,除了the reason why,不是还有the reason that这样的搭配吗,那么什么时候用why,什么时候用that,能举些例子吗)
4.The teacher demanded that the homework ____ before eleven.
A.hand in B.should hand in C.must be handed in D.be handed in
D (不是虚拟语气的宾语从句,中有表示愿望建议命令等动词如demand等词,谓语动词用should+动词原形,should可以省略,那么为什么不选A跟B而选D?)
5.____ what to do,he asked his teacher for help.
A.Not known B.Not knowing C.Not to know D.Having not known
B (莫非是固定搭配?为什么不选D)
第二位第一题结实得比较详细...但最好是回答我所有的问题