介词：
是一种用来表示词与词,词与句之间的关系的词。在句中不能单独作句子成分。介词后面一般有名词代词或相当于名词的其他词类，短语或从句作它的宾语。
介词和它的宾语构成介词短语，在句中作状语，表语，补语，定语或介词宾语。
例： infrontof在……前面 infrontof意思是“在……前面”，指甲物在乙物之前，两者互不包括；
          其反义词是behind（在……的后面）。
例：Therearesomeflowersinfrontofthehouse. 房子前面有些花卉。
常见类型：
1、介词+名词形式：
of course当然，自然，无疑 ；in detail详细地 ；on duty值班，上班
2、动词+名词形式：
take care小心，当心 ；tak ecare of照顾，照料  ；take place发生，进行
3、动词+介词形式：
ask for请求，要求  ；arrive at达成，得出 ； call for邀请，要求，需求
4、动词+副词形式：
come up走近，上来，发生，被提出 ； get in进入，收获，收集
小学常见介词短语：
1. wait for 
等候  Wait for me. I want to go shopping with you.
2. help ---with--- 
帮------干------  I can help my mom with some housework.
3. at home
在家 He was not at home yesterday.
4. hold on
保持，别挂机  Hold on, please. He’s writing an e-mail in the study..
5. on foot
步行  I go to school on foot.
6. get to
到达  I usually get to school at 8:00 am.
7. get on
上车   Get on the No. 28 bus when it stops.
8. get off
下车   Get off at the third station.
9. turn on
打开 It’s dark in the room. Please turn on the light.
10．turn off
 关闭    We should turn off the light before we leave.
11. on holiday
度假  My family are going to Canada on holiday.
12. play with
(与)------玩  I can play with the snow in winter.
13. a glass of
一杯  There is a glass of water on the desk.
14. put on
穿上 It’s cold today. Put on your sweater please.
15. take off
脱下  It’s hot now. Take off your coat.
16. put away
放好  Put away your books. We are going to have a P.E class.
17. look for
寻找  I am looking for my dog.
18. on time
准时  I get to school on time every day.
19. in time
及时   The man fell down. The doctors came in time.
20. go on a trip
去旅行  We are going on a trip tomorrow.
21. at night
在深夜 The policeman usually works at night.
22. be grateful to
感激某人   I am very grateful to my mother.
23. listen to
听------   I like listening to music.
24. pass ---to---
给------传递------ He passes the ball to Mike.
25. fly into
飞进------   The ball flies into John’s face.
26. run into
跑进……  I run into the hotel.
27. what for
 为什么   But what for?
28. come on
加油！ Come on!