You hit the nail on the head. 你这话击中了要害。

　　Put the book on the shelf， please.

　My mother was born on April 14， 1947.

　　(哪一年用in，具体到某一天用on)

　　He left Beijing for home on the morning of July 2.

　　(in the morning ，具体到某一天的上午、下午、晚上用on )

　　On the eve of their departure， they gave a farewell banquet.

　　(on the eve of 在……前夕)

　　We usually get up late on Sunday morning.

　　On his return he told us about the meeting.

　　They will go on a visit to Asia. (go on a visit=visit )

　　He is here on business. (be on business 做生意)

　　She is away on a trip. (on a trip 旅行)

　　The workers at the airport is on strike. (be on strike 罢工)

　　When we came back， we found our house on fire.

　　(on fire 着火)

　　The professor is making a speech on the current situation.(关于)

　　This house is on sale. (on sale 出售)

　　Who’s on duty today?

　　The girl insists on leaving home and depends on herself for a living.

　　(insist on 坚持 depend on 依靠，依赖)