如：在21世纪in the twenty-first century;在秋天in autumn;在早上in the morning.还可以用于表示“从现在起,多长时间以后或多久以后”的短语中3、on只要用于表示星期几,具体某一天或某一天的早、午、晚或用在节日前.如：在中秋on Mid-autumn Day；在六一on June 1st4、since,from和for(1)since指从某时一直延续至今,后接时间点,主句用完成时.如：He has studied English since 2000(2)from说明开始的时间,谓语可用过去、现在、将来的某种时态.如：From now on,I will learn English in the mornings.(3)for指动作延续贯穿整个过程,后接时间段,主句用完成时.如：I have studied English for six years.5、(1)after 表示以过去为起点的某一段时间之后,用于过去时.如：They finished the work after two years.(2)after与时间点连用表示将来某个时间之后.如：I‘ll ring you up after two o'clock.6、“by + 时间点”表示“到......”为止,如果by后加“将来的时间点”应用一般将来时；如果by后跟一个过去的时间点应用过去完成时.如：We had learnd 1,000 English words by the end of last term.到上个学期末,我们已经学习了1,000个英语单词7、“during+时间段”与延续性动词连用表示某期间的动作如：He lives with us during these years8、until用于否定句中,“直到.才”,其前的谓语动词多用瞬间性动词；用在肯定句中,意味“知道.为止”,其前谓语动词多用瞬间性动词.如：I didn't leave until my mother came homeI waited for my mother until she came home9、before和after表示时间,分别意为“在.之前”和“在.以后”.如：Please bring your homework before ten o'clockYou can call me after 8:30.二、表示地点的介词1、表示方位的in,at,onin表示在某一地区之内的某方位（属于该范围）；to表示在某一地区之外的某方位（不属于该范围）；on表示与某地的毗邻关系Fujian is in the southeast of China.Japan is to the east of ChinaKorea is on the east of China.2、over,about和on（1）over 指在.正上方,表垂直在上.如：There is a bridge over the river.(2)above 指在上方,属于斜上方.如：Raise your arms above your head(3)on指在上面,表两物体接触.如：There is a plate on the table.3、at,in和on的用法区别(1)at 表示较小的地方.如：at the bus stop,at home(2)in 表示较大的地方.如：in China,in the world(3)on 表示在一个平面上.如：on the table4、(1) in front of,in the front of在.之前（范围外）.如：There are some trees in front of the classroom (2) in the front of表示“在.的前部”（范围内）Our teacher usually sits in the front of the classroom.(3)before所表示的位置关系和in front of 通用,表示“在.前”,“在.面前”He sits before me.5、below,underbelow表示“在下方或位置低于.”,不一定有垂直在下之意；under表示“在.正下方”.如：There are many bikes under the tree.The coat reaches below the knees三、be made 和be used后介词的选择1、be made常见结构（1）be made in意为：在某地方制造（2）be made of和be made from都可以表示由.制造,但be made of 强调从成品上能看出原材料,而be made from则表示从成品上看不出原材料.（3）be made into被制成（4）be made after仿照.制成（5）be made up of由.组成2、（1）be used to=become used to习惯于（做）...,后接名词、代词或动名词形式.（2）be used to 被用来（做）,后接动词原形 （3）be used for 意义相当于beused to do,for 后接名词或动名词 （4）be used as 意为被当做...来使用 （5）be used by 意为被.使用 （6）used to 意为（过去）常常,后接动词原形四、about1、动词+about+sth.about在词表示“论及,谈起,涉及,着手”等意思：arrange about 安排,argue about 辩论,ask about 询问,bring about 带来,chat about 闲聊,care about 在意,complain about 抱怨,go about 着手,hear about 听说,inquire about 打听,know about 了解,quarrel about 争论,read about 读到,see about 负责处理,read about 谈论,think about 考虑,trouble about 担心,tell about 讲述,worry about 着急2、be+形容词+about+sthabout 在此意思是“为.,对.”：be anxious about 为.着急,be bad about 对.感到不舒服,be busy about 忙于.,be careful about 对.感到不舒服,be certain about 对.有把握,be concerned about 为.感到激动,be crazy about 为.发狂,be excited about 为.感到激动,be happy about 为.而高兴,be mad about 为.发疯,be nervous about 对.感到紧张,be particular about 对.严格,be thoughtful about 对.考虑周到,be uneasy about 为.感到不安 注意：come about 发生,get about (疾病、谣言)流行,turn about 转身,leave about 到处乱放,lie about 随便堆放,put about 打扰；传播,put oneself about 使.发愁.这些短语中about 做副词,此时about 后不能接宾语.