四六級考試?？贾攸c(diǎn)英語語法匯總

1、四六級考試常考英語語法一.定語從句引導(dǎo)定語從句的有關(guān)系代詞as, who, whom, whom, which, that和關(guān)系副詞 when, where, why 等。1 .as引導(dǎo)定語從句（1） as引導(dǎo)定語從句,相當(dāng)于which。如 I am from shanghai, as/which you know。但as引導(dǎo)的定語從句可以放在句首，而which不能；例： As you know, I am from shanghaio）（2） as可作為關(guān)系代詞來引導(dǎo)定語從句，既可以單獨(dú)引導(dǎo)從句，乂可以與主 句中的the same或such相呼應(yīng)，從句中的謂語動詞常省略。2 .關(guān)系代詞tha

2、t與which用法區(qū)別：（1）which可以引導(dǎo)一個(gè)非限制性定語從句，that則不能；（2） which之前可以有介詞，that之前則不能；（3）只能用that,而不能用which的主要情形:當(dāng)先行詞是 all, anything, few, little, much, none, nothing, something 等不定代詞時(shí)；一一當(dāng)先行詞被序數(shù)詞或形容詞最高級修飾時(shí)；當(dāng)先行詞被the very, the only等詞修飾時(shí)。例： Medical researchers are painfully aware that there are many problems to which t

3、hey have not found solutions so far。二.狀語從句1.讓步狀語從句(1) 由 no matter + wh-疑問詞no matter what 和 wh-疑問詞>ever whatever o但wh-疑問詞+ever【whatever】引導(dǎo)的名詞從句則不能用no matter 替換。Take the coat , no matter what coat it is / whatever coat it is .(2) No matter whether.or結(jié)構(gòu)中可將 no matter 省略，形成 whetheror或 whether.or not引導(dǎo)

4、選擇條件句。彳列；The substance does not dissolve in water whether it isjheated or note2.條件狀語從句>翻譯條件狀語從句時(shí)，要注意時(shí)態(tài)的選擇。例；Please come here at ten tomorrow morning if it is convenient for you。條件狀 語從句，用if引導(dǎo)；主句是祈使句，相當(dāng)于將來時(shí)態(tài)，故從句應(yīng)用一般現(xiàn)在 時(shí)。3 .時(shí)間狀語從句彳列； We do not know it until a doctor discovered it by chance o4 .原因狀語從

5、句常見引導(dǎo)原因狀語從句的引導(dǎo)詞有；because, as, now that/since, in that 等。三.名詞性從句1 .主語從句漢語中的“的字結(jié)構(gòu)可譯成英語的主語從句，用what引導(dǎo)，相當(dāng)于the thing thato仞J： What many people have not realized is that read books is a insteresting thingo2 .表語從句In my seventies, one change I notice is that I am more easily to get tired than before o四.比較結(jié)構(gòu)1

6、. as.as【與.一樣】，morethan【比更】，a bit/a little/a lot/even/far/gretly/many/much/sightly/still+形容詞/副詞比較級這些結(jié)構(gòu)。主意： more than 表示'不只是， 只不過；no more.than.=not.any more than., 表示，與一樣不.I彳列：I would prefer shopping online to shopping in a department store because it is more convenient and time-savingoASince my c

7、hildhood I have found that nothing is more attractive to me than readingo2. The more.the more.，越.越"例：The more you explain , the more confused me 03倍數(shù)表達(dá)法A is倍數(shù)+the size/length/width of B【A是B的幾倍大/長/寬】A is倍數(shù)+形容詞或副詞原級+asB【A是B的幾倍】A is倍數(shù)more than B【A是B的幾倍】例： On averaget it is said,visitors spend only

8、 half as much money in a day in Leeds as in London.4,表示與相 比較的短語compare with和in comparison with彳列：Your losses in trade this year are nothing compared with/in comparison with mineo五.情態(tài)動詞1 .情態(tài)動詞中的must, can, could, may, might都表示推測。其中must可能性 最大，can和could其次，may和might最小。2 .情態(tài)動詞完成時(shí)所表達(dá)的意義:could have done本科可能

9、做may/might have done 也許做 ishould have done 本應(yīng)做must have done 肯定做過六.倒裝結(jié)構(gòu)1 .有否定含義的副詞或短語位于句首作狀語，這類詞有：neither, never, no, rarely, hardly.when, little, few, in no case , no sooner.than 等。例：Not until he fanish his work did he realize he was seriously illo2 .含有only的狀語或賓語位于句首時(shí)，其句子的主謂要部分倒裝。例： Not only did he

10、 charge me too much, but he completed his missiono3.虛擬語氣的讓步狀語從句中，在省略了 If的情況下主謂部分倒裝。Had I taken your advice if I had taken your advice , all this misery might have been avoided o七.虛擬語氣1 .虛擬語氣用于非真實(shí)條件句(1)由if引導(dǎo)的非真實(shí)條件句表示對現(xiàn)在過去將來的事實(shí)進(jìn)行假設(shè)時(shí).，主 從，句的謂語動詞形式如下所示表虛擬的時(shí)間If從句謂語形式主句謂語形式現(xiàn)在過去時(shí)Would/should/could/might+ 動

11、詞 原形過去Had+過去分詞Would/should/could/might+have done將來一般過去時(shí)Were to+動詞原形Would/should/could/might+ 動詞 原形Should+動詞原形例：If she had returned an hour latter, Mary would not have been caught in the heave rain。（2）有些介詞或介詞短語含有隱含的條件含義，其虛擬形式與if引導(dǎo)的非真 實(shí)條件狀語從句類似，需根據(jù)從句所用的時(shí)態(tài)，來選擇主句謂語形式。這些詞 包括：without, but for, were it not

12、 for 等。2 .虛擬語氣用于狀語（1） lest, in case或for fear that引導(dǎo)的目的狀語從句中，謂語動詞用 【should+動詞原形】）（2）在as if或as though引導(dǎo)的方式狀語從句中，謂語動詞虛擬式的變化要依 據(jù)對過去，現(xiàn)在，將來的假設(shè)選擇適當(dāng)?shù)膭釉~虛擬式。列：You would better take a sweater with you in case it gets cold °3 .虛擬語氣用于賓語從句中（1）Wish后的賓語從句可用三種謂語動詞形式表示虛擬：一般過去時(shí)表示對現(xiàn)在情況的假設(shè)過去完成時(shí)表示對過去情況的假設(shè)would+動詞原形表

13、示對將來的愿望例：sometimes I wish I were living in a different time and different placeo（2） would rather, would sooner, might as well, would prefer 后面跟虛 擬語氣表示愿望，意為寧愿，但愿，形式為：would ranther/sooner+主語+謂語動詞過去式表示現(xiàn)在或?qū)淼脑竿鹷ould ranther/sooner+主語+動詞過去完成時(shí)表示過去的愿望例：I would rather I had not gone to the party yesterday o（3） if only引導(dǎo)的感嘆句表示但愿，要是.就好了。其用法和wish基 本相同，只是感情色彩更強(qiáng)烈。（4） 在表示命令，建議等動詞后的賓語從句中要求用虛擬語氣形式，謂 語形式為should+動詞原形例：The teacher raquired that we should hand in our homework by Wednesday o4.it is +形容詞/名詞+th