问题
Do you know the reason _________ pilotsturn off the plane’s lights before taking off —The practice is for the passengers toadjust to the dark _________ an emergency.
A:why; for fear that
B:for which; in case of
C:how; for fear of
D:that; in case
B:for which; in case of
C:how; for fear of
D:that; in case
正确答案是：
