No sooner themselves in their seats in the theatre the curtain went up.
A. they have settled; before
B. had they settled; than
C. have they settled; when
D. they had settled;than
网友回答
A. they have settled; before
(答案→)B. had they settled; than
C. have they settled; when
D. they had settled;than
解析：no sooner…than…,hardly…when…结构中，主句应用过去完成时的倒装结构。故选B。