English grammer

朋友，當你看到很多答案的時候，是否感到更困惑，當中的解釋又似是而非
其實首先你要明白，at, 　in,　 on的用法，再看一看字典的例子，或網上有把的例子就會更有把握
Prepositions of Time: at, on, and in
We use at to designate specific times.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
The train is due at 12:15 p.m.
We use on to designate days and dates.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
My brother is coming on Monday.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
We're having a party on the Fourth of July.
We use in for nonspecific times during a day, a month, a season, or a year.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
She likes to jog in the morning.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
It's too cold in winter to run outside.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
He started the job in 1971.

圖片參考：http://grammar.ccc.commnet.edu/grammar/gif/cleardot.gif
He's going to quit in August.
即，at是用在指定的時間，而on用在指定的日子，日期；而in是用在沒有指定的時間，月份，季節，年份。
所以，Monday morning是有指定的日子的早上，但卻沒有指定準確的時間；故此，不用in, at；而是要用on
如Cambridge Dictionary有一例：
Would you mind telling me what you were doing on the afternoon of Friday the 13th of March?

而【生活美語】也有例子：http://education.atnext.com/index.cfm?fuseaction=Article.View&articleID=6303044&issueID=20061009
A:Thank you for coming and you must come and see us again.
甲 ： 謝 謝 你 光 臨 ， 你 一 定 要 再 來 見 我 們 吧 。
B:Sure, let´s keep in touch.
乙 ： 當 然 會 ， 我 們 保 持 聯 絡 。
A:And don´t forget to give me a call on Monday morning.
甲 ： 勿 忘 記 星 期 一 早 上 打 電 話 給 我 。
B:I won´t. I´ll ring you around ten.
乙 ： 不 會 忘 記 ， 我 會 大 概 十 點 鐘 打 給 你 。

想，你現在已經很有把握，答案是甚麼！

in morning

On Monday morning ( because Monday go first and it is use 'on')

you remeber when you see the word alking about moring,afternoon,noon,midnight..etc. it will also use in

you remeber when you see the word talking about monday,tuesday,wednesday.. etc and january,feburary,march...etc. They will also use on

in!!!

We use the preposition (on) before day,just like Monday/Sunday/Wednesday...etc/so we must use on Monday morning.

That is on Monday . It's because Monday is use on.

In Monday morning

格式:
-in the morning
-in the afternoon
-in the evening