In science fiction we read of flying saucers travel through ____ space, so people want to have ____ better

knowledge of the universe. [ ]

A. the; a

B. /; / 

C. the; /

D. /; a

加热停止后，必须等（），才能拆卷.

A.发卷冷却

B.发卷很热

C.发卷温热

D.随便什么时候