介词：是虚词，它不能单独充当句子成分，常常放在名词或代词之前，与之一起构成介词短语，共同充当句子成分。
主要分为三类：时间介词、地点介词、方式介词一.时间介词A) 表示“在何时”常用介词in，on，at等in的用法:1）用在世纪、四季、年、月前in 21st century in winter in 2009 in January2）泛指一天中的上午、下午、晚上in the morning in the afternoon in the eveningon 的用法:1）用在星期、节日前o n Monday on Teacher’s Day2）用在具体某一天的上午、下午、晚上之前以及具体某一天前on the morning of June 5 on Monday afternoonon a cold winter evening on March 1stat 的用法:1）用在钟点前at six at eight2）用在固定词组中at noon at night注：如果night 前有修饰词，表示具体的夜晚用one.g.：on a rainy nightB. 表示“在…..期间”常用介词during，from…to…, for等during the winter holiday 寒假期间during the last two years 在过去的两年中for a long time 好久for three years 三年from Monday to Friday from July to AugustC. 其它表示时间介词1）in 与after 表示时间“在……之后”“in+一段时间”表示将来一段时间之后，通常与将来时态（一般将来时和过去将来时）连用。
“after+一段时间”表示一段时间之后，通常与过去时连用e.g. I hear he’ll be back in a month.Mr.Black. got to Hangzhou after a few days.2) before与after都常用于时间点前before 表示“在……之前,早于……”after 表示“在……之后”（与时间点连用表示将来某个时间之后）e.g. I’ll be free before five o’clock tomorrow.She always watches TV after supper.I’ll ring you up after two o’clock.3) since 与for 常用于现在完成时中引导时间状语。
since 用于时间点前for 用于时间段前e.g. He has been a teacher since 1995.She has lived here for 20 years.4) by 与since 表示时间的用法.by 表示一个瞬间动作发生在某一时间点或在某一时间之前.Since表示从以前某时一直到现在仍在继续，一般只用于完成时态的句子中。
e.g. Jack has studied Chinese in this school since 2000.All of us must be at the school gate by six tomorrow morning.我们大家都得在明天早上6点钟之前到达学校门口。
5） until 与till 意为“直到……”常用于not…until…结构中。
表示“直到……才……”,until 后跟时间点。
e.g. The meeting will last till four o’clock.会议一直开到4点。
She didn’t leave the swimming pool until closing time.她直到关门时才离开游泳池。
6） between 常与and 连用。
表示“在……之间” ，后跟表示“时间点”的名词。
e.g. She was at Middle School between 1979 and 1985.习题：1. Gina was born ________ 1999. She is old enough to go to school（06中考）A. toB. onC. atD. in2. We traveled all night to London and got there ________ Sunday morning.（07中考）A. forB. onC. atD. to3. Peter usually gets up early ________ the morning.（08中考）A. onB. inC. atD. of4. I usually do some cleaning ________ Sunday morning.（10朝阳一模）A. inB. atC. onD. to5. Li Lei often goes to school ________ 7:10 in the morning.(10海淀一模)A. atB.forC.onD.in6. What a healthly boy! He runs ________ the morning every day.(10海淀二模)A.inB.onC.atD.for7. — When was the sports meeting held?—________ April 28.（10宣武一模）A. ToB. AtC. OnD. In8. I usually get up ________ eight o’clock on weekends.(10朝阳二模)A.atB.onC.inD.to9. I often stay at home ________ Sunday.（10通州二模）A. inB. atC. onD. with10. Father’s Day will come ________ June 20th this year.（10西城一模）A. onB. atC. inD. to11. Einstein, the famous scientist, was born ________ March, 1892.(09中考)A. atB. onC. inD. to12. Some volunteers from Beijing arrived in Shanghai ________ April 29 to work for the WorldExpo.(10中考)A.onB.atC.ofD.to13. My uncle is coming to Beijing ________ the morning of May 15.(10东城一模)A.inB.onC.atD.to14. I have seven classes ________ Monday. It’s really a busy day.（10丰台一模）A. atB. inC. ofD. on15. Mr.Black is a hardworking engineer. He often stays up late ________ night.(10东城二模)A.atB.onC.aboutD.to二．地点介词A. in，at 与on表示方位用法in 表示地点，“在……内” ，用于内部。
at 表示“在某地”时，后接小地方，大地方用in。
on“在……上面，在靠近……的地方” ，用于表面接触，指在一个平面上。
on the wall“在墙表面挂着” in the wall “在墙内”There is a hole in the wall.注：表示树上结出果实用on，外来之物停、落在树上用in.B. in，on 和to 表达地区方位in：表示某地在一个大的地区范围内的某一方位。
e.g. Shandong is in the east of China.on: 表示两地区的毗邻或“在……之畔” 用one.g. Korea is on the east of China.to: 在某地范围之外的某个方向用toe.g. Japan is to the esat of ChinaC. across, over与throughacross: 强调从某个平面的一边到另一边，“横过”through：指从某个立体空间内穿过，顺着通过……over: 侧重越过某种障碍物等e.g.The Great Wall goes from west to east,across the desert,over the mountains,through the valleys,till it arrives at the sea.长城从西到东，穿过沙漠，越过高山，跨过深谷，直达海边。
D. “上面” 、“下面”的表达over：表示在上方，强调在物体的正上方。
under：表示在下方，强调在物体的正下方。
above：表示在上方，不一定是正上方，有时也可指温度、海拔等的刻度。
below：表示在下方，不一定是正下方，有时也可指温度、海拔等的刻度。
e.g. L ook，you’ll see a bridge over the river.We can see a village below the mountain when we stand on the top of the hill.E. 英文中某些动词其后要接人，然后接“介词+the+身体部位”注：如果身体部位较软用in，硬的部位用one.g. John hit Jack in the face.He caught the boy by the arm.习题：1. Look at the map ________ China ________ the wall,please.A.of;inB.in;onC.of;on2. There are two windows ________ the right wall, there is a map ________ the left wall.A.in;onB.in;inC.on;onD.on;in3. A little monkey is playing ________ a tree and there are a lot of bananas ________it.A.on;onB.in;onC.on;inD.in;in4.Shanghai is ________ the west of Japan.A.toB.inC.onD.at5. Hong Kong is ________ the south of China, and Macao is ________ the west of Hong Kong.A.in;toB.to;toC.to;inD.in;in6. Do you know that Fujian is ________ the west of Taiwan?A. toB. inC. on三．方式介词A. in 指使用某种语言、工具的具体类型等。