1、一種虛詞。不能單獨作句子成分，它只有跟它后面的賓語一起構成介詞短語，才能在句子中起作用。

　　有：in, on, under, with, behind, about, near, before, after, for, to, up, down, from, in front of, out of,

　　from…to…, at the back of…

　　2、表示時間的介詞有：at, on, in。

　　（1）at表示"在某一個具體的時間點上"，或用在固定詞組中。如：at ten

　　o'clock, at 9:30 a.m., at night, at the weekend…

　　（2）on表示"在某日或某日的時間段"。如：on Friday, on the

　　first of October, on Monday morning…

　　（3）in表示"在某一段時間（月份、季節）里"。如：in the afternoon,

　　in September, in summer, in 2005…

　　3、in一詞還有其他的固定搭配，如：in blue（穿著藍色的衣服），in English（用英語表達），take part in（參

　　加）。

　　練一練：

　　1、選用括號內恰當的介詞填空。

　　1) What's this _______ ( at, on, in ) English?

　　2) Christmas is _______ ( at, on, in ) the 25th of December.

　　3) The man_______ ( with, on, in ) black is Su Hai's father.

　　4) He doesn't do well  _______ ( at, on, in ) PE.

　　5) Look at those birds  _______ ( on, in ) the tree.

　　6) We are going to meet  _______ ( at, on, in ) the bus stop  _______ ( at, on, in ) half past ten.

　　7) Is there a cat    _______ ( under, behind, in ) the door?

　　8) Helen's writing paper is  _______ ( in, in front of ) her computer.

　　9) We live _______ ( at, on, in ) a new house now.

　　10) Does it often rain   _______ ( at, on, in ) spring there?

　　2、圈出下列句子中運用不恰當的介詞，并將正確的答案寫在橫線上。

　　1) Jim is good in English and Maths.

　　2) The films were in the ground just now.

　　3) They are talking to their plans.

　　4) How many students have their birthdays on May?

　　5) Women's Day is at the third of March.

　　6) I can jog to school on the morning.

　　7) Did you water trees at the farm?

　　8) Can you come and help me on my English?

　　9) I usually take photos in Sunday morning.

　　10) What did you do on the Spring Festival?