时间介词表示法:
在具体某一天用on。如:on Monday, on the afternoon of June 1st
在几点钟用at。如:at 8:00, at a quarter past ten.
在大于一天的时间里用in。如:in May, in a week, in the year 1992, in September.
for后面接一段时间。如:for a week, for a year, for three days, for several months.
in 和for的区别:
in在……内
for表示时间长度