常用in、on、at作介词开头的词组答:时间time in in 1999, in 20 century, in a flash(瞬时), in a lucky hour(在幸运时刻), in a minute, in a second, in a short time, in a while, in a wink(一瞬间) in advance(预先), in an emergency(在紧急地时候), in an evil hour(在不幸地时刻), in an instant, in ...