概括地说in后接概括的时间:年,月,季节,早晚(不带限定词时) 例如:in 2011,in June,in summer,in the morning/ afternoon/ evening on接稍微具体的时间:日,星期,具体某天的时间段(有修饰限定词) 例如:on June 30th,on Thurday,on a rainy day,on a foggy morning at接具体的时间点:时刻 at seven o'clock,at half past eight
年、月前面用 in in 2005, in June, in January 2008 ... 日期、星期几 用 on on Monday, on (the) weekend, on August 8, 2008, on June 1st ... 时间,几点几分 用 at at six in the morning, at 8 o'clock, at 2:45pm ... 直接跟 time 这个词 in time 及时 on time 准时