问题

Scarcely _____ raining _____ the PLA fighters started on their way again.
A:it had stoppedbefore
B:it had stoppedthen
C:had it stoppedthan
D:had it stoppedwhen
B:it had stoppedthen
C:had it stoppedthan
D:had it stoppedwhen
正确答案是: