It will be quite a long time she is back again so don’t be too cross with her.A. beforeB

问题补充：

It will be quite a long time she is back again, so don’t be too cross with her.

A. before

B. since

C. that

D. until

答案：

(答案→)A. before

B. since

C. that

D. until

解析：考查连词，since表示自从…；until直到…；时间段+ before，过了多久就……；before主要引导时间状语从句，意为“先于”“…之后才”“(不多久)就…”。当主句是将来时时，从句谓语动词须用现在时；当主句是一般过去时或过去完成时时，从句常用过去时。before引导的时间状语从句不能用于否定式。