1.After my graduation I will have to go ___ I am needed.

1.After my graduation I will have to go ___ I am needed.
A.when B.where C.as D.which
2.Above the land and water ____ with a depth from 50 to 200 miles
A.a layer of air is B.will a layer of air be C.a layer of air will be D.is a layer of air
3.A:Do you think it's going to rain over the weekends?
B._____
A.I don't believe B.I don't believe it C.I believe not so D.I believe not
4.On a cold winter day,the man left his wife and enght-month-old daughter,____.
A.and never to be heard of B.to be never heard of C.never to be heard of D.and never being heard of
5.Every few ___ along the Great Wall there used to be watchtowers.
A.hundreds metres B.hundreds of metres C.hundred metres D.hundred of metres
6.I remember ____ to help us if we ever got into trouble
A.once offering B.him to offer C.him once offering D.to offer him