what was he doing ______ you saw him last night如题.a.while b.when _英语解答

what was he doing ______ you saw him last night
如题.a.while b.when c.before d.after
是用when么?怎么不是while

人气：392 ℃　时间：2019-10-11 15:02:03

解答

while是时间段
when 表时间点
你看到他的一眼是瞬间动作