《英語(yǔ) 語(yǔ)法總結(jié)》word版.doc

英語(yǔ)語(yǔ)法總結(jié)全集名詞和主謂一致一、 名詞的分類 英語(yǔ)中名詞主要可以分為可數(shù)名詞和不可數(shù)名詞。1可數(shù)名詞 可數(shù)名詞一般都有單復(fù)數(shù)。單數(shù)時(shí)，名詞前可加不定冠詞a/an；復(fù)數(shù)時(shí)，前面可加數(shù)詞，名詞本身要改成復(fù)數(shù)形式。 可數(shù)名詞的復(fù)數(shù)有規(guī)則和不規(guī)則兩種變化。規(guī)則的名詞，只要在單數(shù)名詞之后加“s”，“es”或去“y”加“ies”就行，如：an umbrella, twelve umbrellas；a factory, three factories。不規(guī)則的名詞變化則要靠積累記憶，如：a mouse, ten mice；a policeman, six policemen。 有少數(shù)可數(shù)名詞，如sheep，works（工廠），Chinese等，它們的單復(fù)數(shù)同形：a sheep, four sheep；a chemical works, five chemical works。 此外，還有一些可數(shù)名詞只有復(fù)數(shù)形式，如clothes，trousers，cattle，police，people(人，人民)等。 英語(yǔ)名詞中還有一些合成詞，它們的復(fù)數(shù)形式有三種可能：1）后面的部分變成復(fù)數(shù)形式：grown-ups，boy students，grandchildren。2）前面的部分變成復(fù)數(shù)形式：passers-by，lookers-on，sons-in-law。3）前、后都變成復(fù)數(shù)形式：men doctors，women drivers。2不可數(shù)名詞 不可數(shù)名詞沒(méi)有單復(fù)數(shù)的變化，前面也不能加a/an，或數(shù)詞。但是我們可以用量詞來(lái)表示不可數(shù)名詞的數(shù)量，單復(fù)數(shù)表現(xiàn)在量詞上，如：a piece of paper；two pieces of paper。 在有些情況下，不可數(shù)名詞也可用a/an，表“一種”、“某種”的意思，如have a wonderful time，receive a good education，be made into a fine paper。 有時(shí)為了表示量大，不可數(shù)名詞的后面也可加“s”，如sands，ashes，waters等。 但是我們?cè)趯W(xué)習(xí)不可數(shù)名詞的時(shí)候，特別要記住英語(yǔ)中有一些名詞，它們無(wú)論在什么情況下，前面都不能用a/an，后面也不可加“s”，如weather，information，等。3有的名詞既可是可數(shù)名詞，也可是不可數(shù)名詞 英語(yǔ)中有相當(dāng)一部分的名詞，既可以是可數(shù)，也可以是不可數(shù)，它們的意義有時(shí)略有不同，有時(shí)則完全不同。如：difficulty, success, time, work，paper，glass，等。4用于表示可數(shù)與不可數(shù)名詞的數(shù)量“多”“少”的常用詞和詞組 跟可數(shù)名詞連用的如：few, a few, many。 跟不可數(shù)名詞連用的如：little, a little, much。 可數(shù)與不可數(shù)都能用的是：a lot of , plenty of。二、主謂一致1通常被看作單數(shù)的主語(yǔ)部分1）不定式、動(dòng)名詞和主語(yǔ)從句。 eg. To see is to believe. Seeing is believing. What he said was different from what he did.2）表示“時(shí)間”“距離”“金錢數(shù)量”的名詞。 eg. Twenty years is quite a long time. 10 kilometers doesnt seem to be a long distance to Mira. 300 dollars is too much for this old coin.3）數(shù)學(xué)式子。 eg. Two plus five is seven.4）書(shū)報(bào)雜志、國(guó)家、單位的名字。 eg. The Times is published daily. The United States is a big country.5）前面用a kind of, a sort of或this kind of, this sort of等詞組的名詞。 eg. This kind of tree(s) often grows well in warm weather.6）代詞either, neither作主語(yǔ)。 eg. Either of the plans is good. Neither of them was carrying a weapon.7）many a/ more than one 加單數(shù)名詞，或one out of加復(fù)數(shù)名詞作主語(yǔ)。 eg. Many a young man has tried and failed. More than one employee has been dismissed. One out of ten thousand computers was infected with the virus. 2通常被看作復(fù)數(shù)的主語(yǔ)部分1）一些只有復(fù)數(shù)的名詞如clothes, trousers, police等。 eg. These trousers are dirty.但要注意比較：A new pair of trousers is what you need。2）代詞both作主語(yǔ)。 eg. Both of them have received high education.3需要進(jìn)行分析才能確定的主語(yǔ)部分1）代詞all, some,作主語(yǔ)。 所代的名詞是可數(shù)名詞，就看作復(fù)數(shù)；是不可數(shù)名詞，就看作單數(shù)。 eg. All is ready. (= Everything is ready.) All are present. (= All the people/students. are present.)2）a lot of, lots of, plenty of, some, any, 20% of, half of.等詞組作主語(yǔ)。 所修飾的名詞是可數(shù)名詞，就看作復(fù)數(shù)；是不可數(shù)名詞，就看作單數(shù)。 eg. 70% of the surface of the earth is covered with water. 90% of the graduates from the high school go to university.3）關(guān)系代詞who, which, that作主語(yǔ)。 由先行詞決定單、復(fù)數(shù)。 eg. The student who is talking with the principal is Tom. The students who have chosen physics will have a test tomorrow. 但要注意one of .與only one of.所修飾的先行詞。 eg. He is one of the students in our class who have been to Beijing. He is the only one of the students who has been to London.4）一些表示集體意義的名詞如family, team, class等。 當(dāng)這些名詞強(qiáng)調(diào)的是一個(gè)整體時(shí)，看作單數(shù)；當(dāng)它們強(qiáng)調(diào)的是這個(gè)集體中的成員時(shí)，看作復(fù)數(shù)。 eg. Happy families are all alike; every unhappy family is unhappy in its own way. My family are all early risers.4出現(xiàn)在句首，用連詞或介詞連接的兩個(gè)名詞或詞組1）用both.and.連接的兩個(gè)名詞看作復(fù)數(shù)。 Both Kate and Jean are football players.2）用or, either.or., neither.nor., not only.but also.連接的兩個(gè)名詞，由靠近動(dòng)詞的名詞決定單復(fù)數(shù)。 Either you or I am to go. Not only the students but also the teacher has to observe the rules.3）用as well as, (together) with, like, besides, but, except等連接的兩個(gè)名詞，由第一個(gè)名詞決定單復(fù)數(shù)。 eg. His eyebrows as well as his hair are now white. No one but these two peasants has been there.實(shí)際上這些都是介詞短語(yǔ)提前，不是并列的主語(yǔ)。4）用and連接的兩個(gè)名詞有幾種情況： a)看作復(fù)數(shù)。 eg. Tom and Mary are primary pupils. b) 在有every . and every ., each . and each . 的時(shí)候；或用and連接的兩個(gè)名詞表示的是一件東西或一個(gè)人時(shí)，看作單數(shù)。 eg. Every boy and every girl in our country has the right to go to school. Bread and butter is what he eats for breakfast every day.高考真題試析：01年23題As a result of destroying the forests, a large _ of desert _ covered the land. A. number; hasB. quantity; hasC. number; haveD. quantity; have選B。因?yàn)榈谝桓窈蟮拿~desert是不可數(shù)名詞，所以A、C兩項(xiàng)排除；又desert做主語(yǔ)，謂語(yǔ)要用單數(shù)形式。02年（春）26題He is the only one of the students who _ a winner of scholarship for three years. A. isB. areC. have beenD. has been選D。因?yàn)槎ㄕZ(yǔ)從句的先行詞是由only one of修飾，所以應(yīng)看成單數(shù)；另外后面有時(shí)間狀語(yǔ)for three years，所以用現(xiàn)在完成時(shí)態(tài)。03年28題 The young dancers looked so charming in their beautiful clothes that we took _ pictures of them. A. many ofB. masses ofC. the number ofD. a large amount of選B。 空格后面的名詞是復(fù)數(shù)，所以不可以選D，而many后不跟of用，所以A項(xiàng)排除；the number of的確是放在可數(shù)名詞復(fù)數(shù)的前面，但意思是“.的數(shù)量”，不符合題意。03年（春）28題 Where and when to go for the on-salary holiday _ yet. A. are not decidedB. have not been decided C. is not being decidedD. has not been decided選D。此句是不定式做主語(yǔ)，看成單數(shù)。而C項(xiàng)的時(shí)態(tài)不對(duì)，所以只有D。04年（春）30.題No one in the department but Tom and I _ that the director is going to resign. A. knowsB. knowC. have knownD. am to know選A。謂語(yǔ)動(dòng)詞應(yīng)該跟no one一致，所以選A。05年（春）28題We have only a sofa, a table and a bed in our new apartment. We need to buy _ more furniture. A. anyB. manyC. littleD. some選D。后面的名詞是furniture，不可數(shù)。而且整句的意思是“要買些家具”,是肯定意義，所以選D。05年（春）42題Telephone messages for the manager _ on her desk but she didnt notice them. A. were leftB. was leftC. was leavingD. were leaving選A。句子的主語(yǔ)是messages，是復(fù)數(shù)，另外它與動(dòng)詞“留（在桌上）”的關(guān)系是被動(dòng)。05年31題Professor Smith, along with his assistants, _ on the project day and night to meet the deadline. A. workB. workingC. is workingD. are working選C。謂語(yǔ)的單復(fù)數(shù)跟Professor Smith一致，應(yīng)該是單數(shù)。動(dòng)詞的時(shí)態(tài)與語(yǔ)態(tài)一、動(dòng)詞的時(shí)態(tài) 英語(yǔ)的動(dòng)詞可以有十六種變化，但現(xiàn)在常用的是十二種，其中有九種是高中學(xué)生必須掌握的，還有三種只要理解。現(xiàn)以動(dòng)詞do為例，十二種時(shí)態(tài)的形式列表如下：一般進(jìn)行完成完成進(jìn)行現(xiàn)在do/doesis/am/are doinghave/has donehave/has been doing過(guò)去didwas/were doinghad done*had been doing將來(lái)shall/will do*shall/will be doing*shall/will have done過(guò)去將來(lái)would do（打星號(hào)的為理解項(xiàng)目）1一般現(xiàn)在時(shí)態(tài) A)意義：現(xiàn)階段經(jīng)常反復(fù)發(fā)生的動(dòng)作或現(xiàn)在的狀態(tài)。 eg. He gets up at six every morning. There is a big tree in the back yard. B)常用的時(shí)間狀語(yǔ)：always, often, usually, sometimes, seldom, never, every day, once a week,等。 C)表示一種真理、自然規(guī)律等，在間接引語(yǔ)中也仍然用一般現(xiàn)在時(shí)態(tài)。 eg. The scientist explained that the earth goes round the sun, but no one believed him then. D)在時(shí)間、條件等狀語(yǔ)從句中，代替將來(lái)時(shí)。 eg. If he is not busy, he will come to the party tomorrow. E)注意第三人稱單數(shù)時(shí)，動(dòng)詞后面要加“s”。2 一般過(guò)去時(shí)態(tài) A)意義：過(guò)去的動(dòng)作或狀態(tài)。注意，即使是剛剛發(fā)生的事情，時(shí)間非常短，也要用過(guò)去時(shí)態(tài)。如：Why! Its youMary! I didnt know you were here! B)常用的時(shí)間狀語(yǔ)：yesterday, last week, 3 years ago, just now, 等。 C)動(dòng)詞過(guò)去式的規(guī)則變化（加ed）和不規(guī)則變化。3一般將來(lái)時(shí)態(tài)A)意義：將來(lái)要發(fā)生的動(dòng)作或狀態(tài)。B)常用的時(shí)間狀語(yǔ)：tomorrow, next moth, in two weeks, 等。C)除了用shall/will之外的將來(lái)表達(dá)法： a) is/am/are going to do，意為“打算、準(zhǔn)備、馬上就要”。 eg. Its going to rain. b) is/am/are to do，意為“（計(jì)劃好/安排好）要.” eg. The new underground railway is to be opened to traffic next year. c)is/am/are about to do，意為“馬上就要”。 eg. Hurry up! The plane is about to take off. d) 某些動(dòng)詞（主要是一些表示位置移動(dòng)的動(dòng)詞）可用一般現(xiàn)在時(shí)態(tài)或現(xiàn)在進(jìn)行時(shí)態(tài)表示將來(lái)的動(dòng)作。 eg. The train leaves for Beijing at 8:30 this evening. He is going to London next week.4現(xiàn)在進(jìn)行時(shí)態(tài)A)意義：表示在說(shuō)話的同時(shí)或最近一個(gè)階段正在發(fā)生的動(dòng)作。 B)常用的時(shí)間狀語(yǔ)：now, these days, at present, at the moment, 等。 C)有時(shí)可以和always, constantly, forever等時(shí)間狀語(yǔ)連用，表示說(shuō)話人的某中特殊的感情。 eg. He is always thinking of others. Mrs Smith is constantly quarrelling with her neighbours. D)有些瞬間動(dòng)詞可以用進(jìn)行時(shí)態(tài)表示“馬上就要.” eg. The old man is dying. E)英語(yǔ)中有些表示狀態(tài)、感覺(jué)、心理活動(dòng)的動(dòng)詞沒(méi)有進(jìn)行時(shí)態(tài)，如know, understand, believe, like, love, see, hear, seem, 等等。5過(guò)去進(jìn)行時(shí)態(tài) A)意義：表示過(guò)去某個(gè)時(shí)刻正在做的動(dòng)作。 B)常用的時(shí)間狀語(yǔ)：this time yesterday, at 9:00 last night, 等。 C)有些動(dòng)詞（主要是一些表示位置移動(dòng)等的動(dòng)詞和瞬間動(dòng)詞）的過(guò)去進(jìn)行時(shí)態(tài)可以表示過(guò)去將來(lái)的意義。 eg. I was told that she was leaving for Australia the next morning.*6將來(lái)進(jìn)行時(shí)態(tài)A)意義：表示將來(lái)某個(gè)時(shí)刻正在發(fā)生的動(dòng)作。 B)常用的時(shí)間狀語(yǔ)：this time tomorrow, at 9:00 next Sunday morning, 等。 eg. What will you be doing at 9:00 on June 7next year?7現(xiàn)在完成時(shí)態(tài)A)意義：a. 表示過(guò)去某個(gè)時(shí)刻開(kāi)始，一直持續(xù)到現(xiàn)在的動(dòng)作或狀態(tài)。（只有部分延續(xù)性動(dòng)詞，如live, work, study, 等可以表示這一意義） eg. I have lived in Shanghai since I was born. He has been married for half a year. b. 表示過(guò)去做過(guò)的某一個(gè)動(dòng)作對(duì)現(xiàn)在的影響。 eg. I have seen this film. Its fantastic! Jack is playing video games, because he has done his homework. B)常用的時(shí)間狀語(yǔ)：a. since 1990, for 9 years,等。 b. already, yet, just, now, this week, never, ever, so far, up till now, lately, in the past/last few years, 等。 C)b組所表示的現(xiàn)在完成時(shí)態(tài)與過(guò)去時(shí)態(tài)的區(qū)別：雖然現(xiàn)在完成時(shí)態(tài)b組表示的動(dòng)作也是發(fā)生在過(guò)去，但它強(qiáng)調(diào)的是與現(xiàn)在的關(guān)系，而過(guò)去時(shí)態(tài)只表示過(guò)去發(fā)生的動(dòng)作，敘述一個(gè)事實(shí)。試比較： eg. 1) He went to Beijing two days ago. He has gone to Beijing. 2) Henry lost his mobile phone yesterday, but found it later. Henry has lost his mobile phone again.D)瞬間動(dòng)詞要表示“一直到現(xiàn)在”，不能直接用“完成時(shí)態(tài)加for”的方式，必須用其他句型。 eg. 他離開(kāi)上海已經(jīng)三天了。 He has left Shanghai. He left three days ago. He has been away from Shanghai for three days. It is three days since he left Shanghai.8過(guò)去完成時(shí)態(tài)A)意義：表示過(guò)去某個(gè)時(shí)刻之前所做的動(dòng)作，即“過(guò)去的過(guò)去”。所以一般要用過(guò)去完成時(shí)態(tài)的話，句子中或上下文一定有一個(gè)過(guò)去時(shí)態(tài)的動(dòng)作或時(shí)間狀語(yǔ)做比較，才能用。 eg. He had learned English before he went to Canada. B)常用的時(shí)間狀語(yǔ)：by the end of last year 等。 C)在用間接引語(yǔ)時(shí)，主句的動(dòng)詞是過(guò)去時(shí)態(tài)，用來(lái)替換直接引語(yǔ)中的過(guò)去時(shí)態(tài)或現(xiàn)在完成時(shí)態(tài)。 eg. He asked the girl, “Where have you been?” He asked the girl where she had been. He said, “I cleaned the classroom yesterday.” He said that he had cleaned the room the day before. D)有些動(dòng)詞（如hope, wish, expect, think, intend, mean, suppose等）的過(guò)去完成時(shí)態(tài)可表示過(guò)去事實(shí)上沒(méi)有實(shí)現(xiàn)的希望、計(jì)劃等。 eg. I had hoped to attend the party, but I was too busy.*9將來(lái)完成時(shí)態(tài) A)意義：表示在將來(lái)某個(gè)時(shí)刻之前將會(huì)完成的動(dòng)作。 B)常用的時(shí)間狀語(yǔ)：by the end of next year等。 eg. You will have studied English for 10 years by the time you finish high school.10現(xiàn)在完成進(jìn)行時(shí)態(tài) A)意義：表示一個(gè)動(dòng)作從過(guò)去開(kāi)始，一直持續(xù)到現(xiàn)在。（同現(xiàn)在完成時(shí)態(tài)的第一種意義） B)常用時(shí)間狀語(yǔ)：since ., for ., so far, up till now 等。 C)現(xiàn)在完成進(jìn)行時(shí)態(tài)與現(xiàn)在完成時(shí)態(tài)的比較： 只有現(xiàn)在完成時(shí)態(tài)的第一種意義的那些動(dòng)詞，它們的現(xiàn)在完成與現(xiàn)在完成進(jìn)行兩種時(shí)態(tài)表示的意義相同，可以互換使用。 eg. I have studied here for 3 years. = I have been studying here for 3 years. 而其他的一些動(dòng)詞，使用兩種時(shí)態(tài)，意義就各不相同了。 試比較： The little boy has read the text.（小男孩已經(jīng)讀過(guò)課文了。） The little boy has been reading the text.（小男孩一直在讀課文。） 試翻譯：1）從上午九點(diǎn)開(kāi)始我就一直在做功課。 I have been doing my homework since 9 in the morning. 2）今天的功課我已經(jīng)做好了。 I have done todays homework.*11過(guò)去完成進(jìn)行時(shí)態(tài)意義：表示從過(guò)去某一時(shí)間開(kāi)始的動(dòng)作一直持續(xù)了一段時(shí)間再結(jié)束。（結(jié)束的時(shí)間點(diǎn)也在過(guò)去） eg. He had been searching for the watch for a half hour when we came back.12過(guò)去將來(lái)時(shí)態(tài) 意義：表示從過(guò)去某一時(shí)間看將要發(fā)生的動(dòng)作或狀態(tài)，一般多用在間接引語(yǔ)中。 eg. He told me that he would read the book a second time.二、動(dòng)詞的語(yǔ)態(tài) 英語(yǔ)中的動(dòng)詞可分為及物動(dòng)詞和不及物動(dòng)詞，以及系動(dòng)詞。及物動(dòng)詞有主動(dòng)語(yǔ)態(tài)和被動(dòng)語(yǔ)態(tài)；不及物動(dòng)詞或動(dòng)詞詞組（如happen, belong to, take place等）和系動(dòng)詞（如become, seem, sound, look, taste,等）沒(méi)有被動(dòng)語(yǔ)態(tài)。1以動(dòng)詞do為例，被動(dòng)語(yǔ)態(tài)的各種時(shí)態(tài)的表達(dá)方式如下表：一般進(jìn)行完成現(xiàn)在is/am/are doneis/am/are being donehave/has been done過(guò)去was/were donewas/were being donehad been done將來(lái)shall/will be doneshall/will be done過(guò)去將來(lái)would be done 各種時(shí)態(tài)在助動(dòng)詞be上表示，動(dòng)作由過(guò)去分詞體現(xiàn)。2注意在動(dòng)詞詞組變被動(dòng)的時(shí)候，原來(lái)詞組中的介詞或副詞不要漏掉。 eg. The villagers took good care of the wounded soldier. The soldier was taken good care of by the villagers.3有些動(dòng)詞既是及物動(dòng)詞，又是不及物動(dòng)詞，這些動(dòng)詞比較少用被動(dòng)語(yǔ)態(tài)。 eg. We begin our class at 8:00 every morning. ? Our class is begun . ? Our class begins at 8:00 every morning.4有少數(shù)動(dòng)詞或動(dòng)詞詞組可用主動(dòng)形式，表示（從中文里我們所感覺(jué)的）被動(dòng)意義。 eg. The book sells poorly. His translation reads better than yours. Who is to blame for the accident?高考真題試析：02年23題 He will have learned English for eight years by the time he _ from the university next year. A. will graduateB. will have graduated C. graduatesB. is to graduate選C。雖然句子的時(shí)間狀語(yǔ)是next year，但是“他從大學(xué)畢業(yè)”是以by the time引出的狀語(yǔ)從句，在狀語(yǔ)從句中，用現(xiàn)在時(shí)態(tài)代替將來(lái)時(shí)態(tài)。02年24題 I feel it is your husband who _ for the spoiled child. A. is to blameB. is going to blameC. is to be blamedD. should blame選A。因?yàn)樵~組be to blame for這一詞組用主動(dòng)形式來(lái)表示中文中“該為某事受到責(zé)備”的被動(dòng)意義。02年29題 “Will you go skiing with me this winter vacation?” “It _.” A. all dependB. all dependsC. is all dependedD. is all depending選B。It all depends.是習(xí)慣說(shuō)法，意思為“要看情況而定了”，不用將來(lái)時(shí)態(tài)，也不用被動(dòng)語(yǔ)態(tài)。03年32.題I thought Jim would say something about his school report, but he _ it. A. doesnt mentionB. hadnt mentionedC. didnt mentionD. hasnt mentioned選C。從前面一句I though可以看出是過(guò)去時(shí)態(tài)，用but連接的兩個(gè)并列句中的動(dòng)作是發(fā)生在同一時(shí)間，所以后面的動(dòng)詞也應(yīng)該是過(guò)去時(shí)態(tài)。04年29題 The first use of atomic weapons was in 1945, and their power _ increased enormously ever since. A. isB. wasC. has beenD. had been選C。因?yàn)榫渥拥臅r(shí)間狀語(yǔ)是ever since，意即“自從那時(shí)起”（“那時(shí)”指前面講到的1945年），所以是現(xiàn)在完成時(shí)態(tài)。04年30題 The number of deaths from heart disease will be reduced greatly if people _ to eat more fruit and vegetables. A. persuadeB. will persuadeC. be persuadedD. are persuaded選D。因?yàn)椤叭藗儭焙汀罢f(shuō)服”是動(dòng)賓關(guān)系，所以用被動(dòng)語(yǔ)態(tài)。05年30題 More than a dozen students in that school _ abroad to study medicine last year. A. sentB. were sentC had sentD. had been sent選B。因?yàn)閷W(xué)生是被送到國(guó)外學(xué)醫(yī)的，所以要用被動(dòng)語(yǔ)態(tài)，而句末 時(shí)間狀語(yǔ)表明要用過(guò)去時(shí)態(tài)。06年27題 Send my regards to your lovely wife when you _ home. A. wroteB. will writeC. have writtenD. write選D。這是祈使句中的狀語(yǔ)從句的動(dòng)詞，所以用一般現(xiàn)在時(shí)態(tài)代替將來(lái)時(shí)態(tài)。06年32題 When he turned professional at the age of 11, Mike _ to become a world champion by his coach and parents. A. expectedB. was expectingC. was expectedD. would be expected選C。根據(jù)整個(gè)句子的意思，可以判斷，是他的教練和父母期盼馬克成為世界冠軍，所以用被動(dòng)語(yǔ)態(tài)，時(shí)間在他7歲的時(shí)候，顯然是過(guò)去時(shí)態(tài)。07年28.題“Did you tidy your room?”“No, I was going to tidy my room but I _ visitors.” A. hadB. haveC. have hadD. will have選A。根據(jù)前面的疑問(wèn)句，可判斷談?wù)摰氖沁^(guò)去的事情，而且回答的前半句也說(shuō)明了時(shí)態(tài)：“我正要打掃屋子，但我有客人來(lái)訪了”是過(guò)去時(shí)態(tài)。07年30題 With the help of high technology, more and more new substances _ in the past years. A. discoveredB. have discoveredC. had been discoveredD. have been discovered選D。全句的時(shí)間狀語(yǔ)是in the past years，是典型的現(xiàn)在完成時(shí)態(tài)的時(shí)間狀語(yǔ)，而且“發(fā)現(xiàn)”與“新的物質(zhì)材料”是動(dòng)賓關(guān)系。情態(tài)動(dòng)詞一、can, may, must 根據(jù)意思與習(xí)慣用法，我們可以把can, may, must分成以下兩組用法，方便學(xué)習(xí)與掌握。1第一組用法見(jiàn)下表（主要在初中的時(shí)候我們所掌握的）：詞義肯定否定疑問(wèn)過(guò)去式can能、會(huì)cancantCan.?couldmay可以maymustnt/may notMay.?mightmust必須mustneedntMust.?must/had toA) can a) can的肯定、否定、疑問(wèn)及過(guò)去式的例句：eg. Computers can do a lot of things for us. Money cannot buy everything.Can you speak French?I could run very fast when I was young. b) can與be able tocan與be able to的意思相近，經(jīng)常可以互換使用，但是be able to除了有一般現(xiàn)在與過(guò)去時(shí)態(tài)之外，還有將來(lái)、完成等時(shí)態(tài)，所以要表示將來(lái)能夠或已經(jīng)能夠做什么事，就要用be able to。 eg. You will be able to communicate with foreigners fluently if you finish the course. The baby has been able to one or two simple sentences. 在用過(guò)去式的時(shí)候，could與was able to的意思不同，could表示的是“當(dāng)時(shí)能夠做某事”的意思，而was/were able to表示的是“當(dāng)時(shí)能夠，并且成功地做到了”的意思。 試比較： Einstein was able to flee Germany when Hitler came into power. I could pass the examination, but I was too careless. c) could在疑問(wèn)句時(shí)用意表示請(qǐng)求，意義同can，是一種比較客氣的表達(dá)方式。 eg. Could you give me a hand?B) maya) may的肯定、否定、疑問(wèn)及過(guò)去式的例句： eg. You may choose anyone here you like. May I leave now? Yes, of course/Sure. Go ahead. No, you mustnt. （注：口語(yǔ)中也能用cannot。）I was told that the boss might come to the office before 9 b)mustnt與may not. mustnt一般是說(shuō)話人表示“不可以”或“禁止”，而may not一般是指按規(guī)定“不允許”的意思。試比較： You mustnt leave the bike here. The sign on the wall reads, “Visitors may not feed the animals in the zoo.” c) may可放在句首，表示“祝愿”。 eg. May our friendship last forever.d) might有時(shí)用在疑問(wèn)句中，只是一種比may更客氣一點(diǎn)，而非過(guò)去式。 eg. Might I have a few words with you, sir?C) must a) must的肯定、否定、疑問(wèn)及過(guò)去式的例句： eg. Everyone must obey the rules. Must I finish the work today? Yes, you must. No, you neednt/dont have to. He told me he must/had to see a doctor tomorrow morning. b) must與have to 用must更強(qiáng)調(diào)主觀上“必須”，而have to 更強(qiáng)調(diào)客觀上的“不得不”。 在間接引語(yǔ)中，主句動(dòng)詞是過(guò)去式時(shí)，用had to多，但must也可以用。 have to有現(xiàn)在、過(guò)去和將來(lái)三種時(shí)態(tài)。 c) must有時(shí)可以表示“偏偏”“非.不可”的意思。 eg. Why must you make such a mess when the visitors are coming?2第二組用法見(jiàn)下表：詞義肯定否定疑問(wèn)過(guò)去式進(jìn)行式can可能/一定/cannotCan.?cant have donecant be doingmay可能maymay not/may have dongmay be doingmust一定must/must have donemust be doinga) can, may, must的第二種用法，是用來(lái)表示說(shuō)話人的一種推測(cè)。其中may與must的區(qū)別其實(shí)是說(shuō)話人對(duì)可能性大小所做判斷的區(qū)別，覺(jué)得可能性大，就用must，可能性小，就用may。而can與may, must是肯定、否定、疑問(wèn)分工的不同。 現(xiàn)在時(shí)舉例：Can Tom be in the classroom? Yes, he must be there. 或Yes, he may be there, but Im not quite sure. 或No, he cant be there, because he hasnt come to school today. 過(guò)去時(shí)舉例： I must have been asleep. I didnt hear your footsteps. David became angry at the meeting. He may have misunderstood what I meant. James cant have forgotten the examination yesterday. There must have been something wrong with him, I believe. b)表示可能性的否定句中有時(shí)也可用may，但意思與cannot有所不同。may not一般解釋為“可能不”，而cannot解釋為“不可能” c)表示可能性，也可以用might和could，但并非may和can的過(guò)去式，而是表示說(shuō)話人覺(jué)得可能性實(shí)在是比較小了，有虛擬的意味。跟may與can一樣，might用在肯定句，could用在否定句和疑問(wèn)句。might do的過(guò)去式是might have done，could的過(guò)去式是could have done。 eg. Could it be Susan at the door? Yes, it might be her.（現(xiàn)在口語(yǔ)中也可用could be回答） *d) could have done也可以用在肯定句里，表示過(guò)去有這種可能，但事實(shí)上沒(méi)有發(fā)生（虛擬語(yǔ)氣的用法）。 eg. It was dangerous to do so. You could have killed yourself!二、shall, will, would1用在一般疑問(wèn)句中，表示征求對(duì)方的意見(jiàn)。第一、第三人稱用shall，第二人稱用will或would。 eg. Shall turn on the TV? Shall my brother go with us? Will/Would you do me a favour?2shall與第二、第三人稱連用，用在肯定、否定句中，表示“命令、允諾、警告、威脅，及說(shuō)話人的意愿和決心”。 eg. You shall do it at once! He shall have the money when he finish his work on time. You shall fail if you dont work hard. If Shylock breaks the law, everything he has shall be taken away from him.3will在陳述句中可用于任何人稱，表示“意愿、意志、決心”等。有時(shí)也可用在條件句中。 eg. I will help you at any time if necessary. The captain will land you safe in Liverpool, if you will be man.4will和would可以表示習(xí)慣性反復(fù)發(fā)生的動(dòng)作，或在某一條件下，一定回發(fā)生的動(dòng)作。這時(shí)，will一般指“現(xiàn)在”，would一般指“過(guò)去”。 eg. Oil will float on water, because it is lighter. He would take a walk after supper when he lived here. 上面例句中的would可以用used to來(lái)替換。used to也表示“過(guò)去常?！?，但used to還隱含了“現(xiàn)在不再這樣了”的意思。而would則沒(méi)有這種意思。 eg. He used to smoke, but he has given it up now.三、should/ought to1可以表示一種必要性、義務(wù)，解為“應(yīng)當(dāng)、應(yīng)該”?？梢耘c任何人稱連用，并用在肯定、否定、疑問(wèn)句中。但疑問(wèn)句時(shí)用should更多一些。 eg. You should/ought to pay more attention to your spelling.2可以表示一種推測(cè)，解為“應(yīng)該是”。用于任何人稱的肯定、否定、疑問(wèn)句。它還有進(jìn)行和完成兩種形式：should/ought to be doing（對(duì)現(xiàn)在正在進(jìn)行的動(dòng)作的推測(cè)）和should/ought to have done（表示與過(guò)去的事實(shí)相反，“本來(lái)應(yīng)該”的意思）。 eg. They should be here by now. The students should be doing the experiment in the lab. You should have come here ten minutes earlier.3should有時(shí)可以表示說(shuō)話人驚訝的感覺(jué)，解為“竟然”。 eg. I have never imagined that he should say so at the meeting.四、need和dare need和dare兩詞，都既可作為情態(tài)動(dòng)詞，又可作為實(shí)意動(dòng)詞，所以復(fù)習(xí)的重點(diǎn)是分清在句子中它們分別是哪種動(dòng)詞。1need解為“需要、必須”。 A) 作為情態(tài)動(dòng)詞時(shí)，多用于疑問(wèn)句和否定句。 eg. Need I do it again? No, you neednt. 注意：與Must I do it again?的意思相近，但用need問(wèn)，問(wèn)的人一般希望得到的是否定的回答；而用must問(wèn)，問(wèn)話的人一般希望得到的是肯定回答。 B) 作為實(shí)意動(dòng)詞，可用于各種句型，是及物動(dòng)詞，可以跟名詞做賓語(yǔ)。 eg. We need another five workers to do the work. C) neednt have done與didnt need to do的區(qū)別 neednt have done和didnt need to do分別是情態(tài)動(dòng)詞用法與實(shí)意動(dòng)詞用法的過(guò)去形式，但是所表示的意義不同。neednt have done意思是“本來(lái)不必”，言下之意是“做了不必要做的事了”；而didnt need to do意思是“當(dāng)時(shí)不必要”，言下之意是“當(dāng)時(shí)不必要，因此可能就沒(méi)有做”。 試比較：She was too nervous to reply, but fortunately she didnt need to say anything. 她緊張得無(wú)法答復(fù)，但幸運(yùn)的是，她那時(shí)什么也不必說(shuō)。 You neednt have mentioned it to him, because he had been told everything before. 你本來(lái)不必跟他提這件事的，之前已經(jīng)有人把一切都講給他聽(tīng)了。2dare解為“敢”。 A) 作為情態(tài)動(dòng)詞時(shí)，多用于疑問(wèn)句和否定句。 eg. Dare you say that to your boss? The little boy dare not face his teacher. 但是dare的固定詞組“I dare say.”，用在肯定句中。 eg. Hell come again, I dare say. 注意：dare作為情態(tài)動(dòng)詞時(shí)，它的過(guò)去式是dared。 eg. The