问题
Tommy, your mum has been out without glasses! — Well, take it easy. _______ she is back home for them.
A:It is long before that
B:It won’t be long since
C:It won’t be long before
D:It will be long before
B:It won’t be long since
C:It won’t be long before
D:It will be long before
正确答案是：
