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第一讲定语从句
一关键词
定语从句：在复合句中修饰某一名词或代词的从句叫定语从句。一般紧跟在它所修饰的先行词之后。
先行词：定语从句所修饰的词叫先行词。
关系词：关系词用来引导定语从句。关系词有关系代词和关系副词之分。关系代词有that, which, who，whom，whose，as等；关系副词有when，where，why等。
关系词可以1) 代替先行词；2) 引导定语从句；3)在定语从句中担当一个成分。
例如：The car which my uncle had just bought was destroyed in the earthquake.句中，the car
为先行词；which是关系词引导是定语从句which my uncle had just bought，同时代替先行词the car在定语从句中作主语。
1.关系代词引导的定语从句
who指人，在定语从句中作主语。
whom指人，在定语从句中作宾语，常可省略。
which指物，在定语从句中做主语或宾语，做宾语时可省略。
that指人时，相当于who或whom；指物时，相当于which。在定语从句中作主语或宾语，作宾语时可省略。
whose 通常指人，有时也可指物，在定语从句中做定语。
Note: whose指物时，常用of which结构来代替：
关系代词在定语从句中作主语时，谓语动词要和先行词的性、数保持一致。
注意：which和as引导非限制性定语从句时，有时并没有特定的先行词，而是代表前面说的整个情况。这时which和as 被看作单数，译作“这一点”，其后的谓语动形式用单数形式。如：He said he was a Frenchman，which／as was not true.
但须注意，as引导的这种定语从句可置于主句之前，which引导的这种定语从句只置于主句之后。如：As is known to all，China is a socialist country. China is a socialist country, as/which is known to all.
2.关系副词引导的定语从句
when指时间，在定语从句中作时间状语。
where指地点，在定语从句中作地点状语。
why指原因，在定语从句中作原因状语。
注意：关系副词引导的定语从句经常可以用“介词+关系代词”引导的定语从句来表示。
介词+关系代词
1)根据动词选择介词。I don't know the foreigner with whom my teacher shook hands.（或I don't know the foreigner whom my teacher shook hands with.)
Note: who和that不能直接位于介词后作宾语；有的短语动词是不能拆开的，常见的这类短语有：look for，look after等。
2)根据先行词选择介词。介词和先行词之间构成习惯搭配，介词一般位于关系代词之前，和从句中的动词不存在逻辑或意义上的关系。
3)介词+关系代词有时可转换为关系副词when，why，where等。
定语从句的关系词时，要看先行词在从句中充当什么成分。
被关系词所代替的部分不可在从句中复现。
3.常用that引导定语从句的情况：
1)当先行词中有“人”又有“物”时，关系词用that不用which。
2)先行词本身是all, few，little，much，any，everything，anything，nothing等不定代词时，关系词多用that。
3)先行词指“人”或“物”，并被形容词最高级、序数词或all，no ,any，every，little，much, little, the only，the very等修饰时通常用that引导定语从句。
二限制性定语从句和非限制性定语从句
限制性定语从句和非限制性定语从句的区别
1.限制性定语从句在形式上不用逗号“，”与主句隔开，是先行词不可缺少的定语，如去掉,主句则失去意义或意思表达不完整。翻译时译成先行词的定语“……的”。
2. 非限制性定语从句在形式上用逗号“，”与主句隔开，是对先行词意义的补充说明，如去掉，主句仍能表达完整的意思，通常译成主句的并列句。
3. 关系词的使用：1) 关系词作宾语在限制性定语从句中可以省略，在非限制性定语从句中不可省略。2) 限制性定语从句可用that引导,而非限制性定语从句不用that引导。3)在限制性定从句中可用who代替whom，而在非限制性定语从句中不可用who代替whom。
第二讲现在完成时，现在完成进行时
一现在完成时
1、构成have/has done
2、用法
I表示过去发生的事对现在具有影响。
1) Justin has disappeared, so Kelly is very sad.
2) The boy is happy. He has caught a bird.
II表示过去开始的动作一直延续到现在或者还将持续下去。
1)I have not seen Justin since Last Friday night.
2) Daniel has lived in Beijing since he came to China.
III表示动作的确切时间不明确或不重要。此时下列词汇经常和现在完成时连用：already, ever, never, for, just, lately/ recently, since, yet。
1) The boy has already come home.
2) I haven't heard anything from him yet.
其中，for + 一段时间，since + 某个时间点。
e.g. We haven't seen him for two days. We haven't seen him since last Monday.
IV表示到现在为止的一段时间内重复的动作。
1) Some villagers say that they have seen UFOs many times.
2) I have advised him to give up smoking many times, but he just won't listen to me.
V 现在完成时还可用于下列句型中：
This/It is the best/ finest/ most interesting … + that- clause,
This/It is the first/ second… time + that- clause, that 从句中的谓语动词一般用现在完成时。
It is/ has been a period of time since + 一般过去时
1) This is the best book that I have read.
2) It is the first time that I have seen the film.
3) It is/ has been a long time since I came to Wuxi.
3、注意
1)现在完成时不和明确的表示时间的词连用，如yesterday, last week, in 1976等。
2)表示短暂意义的动词，如begin, leave, arrive, return, stop, open, go, come, die等，不能与表示一段时间的状语连用。
* Read the following sentences and say T or F .
(1) He has come to Beijing since last year. F
(2) He has been here for three years. T
(3) He has joined the army for three years.F
