1.but when I got to --- the town ought to have been,all I fo

1.but when I got to ___ the town ought to have been,all I found was a school and a petrol station.
A.where B.wherever
C.there D.that
正确答案是A
2.I'll see to it ____ everything is ready in time.
A.whether B.if
C.what D.that
正确答案是D
3.The government has promied to do ___ lies in its power to ease the hardships of the homeless.
A.what B.that C.all what D.which
正确答案是A
4.We had hoped to give you a chance ___ nobody else ever had.
A.as B.such C.as such D.such as
正确答案是D
5.After ___ seemed a very long time,the badly-wounded soldier came back to life.
A.that B.it C.what D.which
正确答案是C
我想知道为什么是这些答案.