问题补充:
—Was it there you were away to see your friend off?
—I’m not sure . But when I got back, it was gone.
A. that
B. which
C. where
D. while
答案:
A. that
B. which
C. where
(答案→)D. while
解析:句意:当你出去送别朋友的时候,它在那里吗?我不确定,但是,当我回来时,它就不见了。while 当…时候,引导时间状语从句,其余答案不符合题意,故选D