四六级考试常考重点英语语法汇总

1、四六级考试常考英语语法一. 定语从句引导定语从句的有关系代词 as, who, whom, whom, which , that和关系副词 when, where，why 等。1. as引导定语从句（1）as引导定语从句，相当于 which。如 I am from shanghai, as/which you know。但as引导的定语从句可以放在句首，而 which不能；例： As you know，I am from shangha。（2）as可作为关系代词来引导定语从句，既可以单独引导从句，又可以与主 句中的the same或 such相呼应，从句中的谓语动词常省略。2. 关系代词tha

2、t与which用法区别：（1） which可以引导一个非限制性定语从句，that则不能；（2）which之前可以有介词，that之前则不能；（3）只能用that，而不能用which的主要情形：当先行词是 all，anything，few， little，much，none, nothing，something 等不定代词时；当先行词被序数词或形容词最高级修饰时；当先行词被the very, the only等词修饰时。例: Medical researchers are painfully aware that there are many problems to which they hav

3、e not found soluti ons so far二. 状语从句1. 让步状语从句（1） 由 no matter + wh-疑问词【no matter what】 和 wh-疑问词 +ever【whatever】。但wh-疑问词+ever【whatever引导的名词从句则不能用 no matter 替换。Take the coat, no matter what coat it is / whatever coat it is .(2) No matter whether or结构中可将 no matter 省略，形成 whether or 或 whetheror not引导选择条件句

4、。例；The substanee does not dissolve in water whether it isheated or not2 条件状语从句 翻译条件状语从句时，要注意时态的选择。例; Please come here at ten tomorrow morning if it is convenient for you 条件状语 从句，用if引导；主句是祈使句，相当于将来时态，故从句应用一般现在时。3. 时间状语从句例; We do not know it until a doctor discovered it by chanee4. 原因状语从句常见引导原因状语从句的引导

5、词有；because as, now that/since, in that三. 名词性从句1. 主语从句汉语中的 的”字结构可译成英语的主语从句，用what引导，相当于the thingthato例： What many people have not realized is that read books is a insteresting thing2. 表语从句In my seventies one change I notice is that I am more easily to get tired than before四. 比较结构1. asas与一样】，morethan【比

6、更】，a bit/a little/a lot/eve n/far/gretly/ma ny/much/sightly/still+ 形容词 / 副词比较级这些结构。注意： more than表示 不只是，只不过 no morethan-unotany more than 表示 与一样不 例：I would prefer shopping online to shopping in a department store because it is more convenient and time-sav ing例: Since my childhood I have found that no

7、thing is more attractive to me than read ing。2. The more the more 越 丫 越”例: The more you expla in , the more con fused me3倍数表达法A is倍数+the size/length/width of B【A是B的几倍大/长/宽】A is倍数+形容词或副词原级+as B【A是B的几倍】A is倍数more than B【A是B的几倍】例: On average it is said,visitors spend only half as much money in a day in

8、 Leeds as in London.4.表示与 相比较的短语 compare with 和in comparison with例: Your losses in trade this year are nothing compared with/in comparison with mine。五. 情态动词1. 情态动词中的 must, can, could, may, might都表示推测。其中 must可能性 最大，can和 could其次，may和 might最小。2. 情态动词完成时所表达的意义：could have done本科可能做may/might have done 也许做

9、了should have done 本应做must have done肯定做过六. 倒装结构1. 有否定含义的副词或短语位于句首作状语，这类词有：neither, never,no, rarely, hardly when little , few, in no case, no sooner tha等。例：Not until he fanish his work did he realize he was seriously ill。2. 含有only的状语或宾语位于句首时，其句子的主谓要部分倒装。例: Not only did he charge me too much but he co

10、mpleted his mission3. 虚拟语气的让步状语从句中，在省略了lf的情况下主谓部分倒装。Had I taken your advice【if I had taken your advice】，all this misery might have bee n avoided七. 虚拟语气1.虚拟语气用于非真实条件句(1)由if引导的非真实条件句表示对现在过去将来的事实进行假设时，主 从，句的谓语动词形式如下所示表虚拟的时间If从句谓语形式现在过去时过去Had+过去分词将来一般过去时Were to+动词原形Should+动词原形主句谓语形式Would/should/could/mi

11、ght+ 动词 原形Would/should/could/might+have doneWould/should/could/might+ 动词 原形例: If she had returned an hour latte，Mary would not have been caught in the heave rai n。(2)有些介词或介词短语含有隐含的条件含义，其虚拟形式与if引导的非真实条件状语从句类似，需根据从句所用的时态，来选择主句谓语形式。这些词 包括： without， but for，were it not for 等。2. 虚拟语气用于状语(1) lest, in case

12、或for fear that引导的目的状语从句中，谓语动词用【should+ 动词原形】(2)在as if或as though引导的方式状语从句中，谓语动词虚拟式的变化要依 据对过去，现在，将来的假设选择适当的动词虚拟式。例： You would better take a sweater with you in case it gets cold3. 虚拟语气用于宾语从句中(1) Wish后的宾语从句可用三种谓语动词形式表示虚拟：般过去时表示对现在情况的假设过去完成时表示对过去情况的假设would+动词原形表示对将来的愿望例: sometimes I wish I were living i

13、n a different time and different place(2) would rather，would sooner，might as well，would prefer 后面跟虚拟语气表示愿望，意为宁愿，但愿，形式为：would ranther/sooner+主语+谓语动词过去式 表示现在或将来的愿望would ranther/sooner+主语+动词过去完成时 表示过去的愿望例: I would rather I had not gone to the party yesterday(3) if only引导的感叹句表示但愿，要是 就好了。其用法和wish基 本相同，只是感情色彩更强烈。(4) 在表示命令，建议等动词后的宾语从句中要求用虚拟语气形式，谓语形式为should+动词原形例: The teacher raquired that we should hand in our homework by Wednesday4.it is +形容词/名词+that结构