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biosynthesis of RNA RNA的生物合成.ppt
13冠词的用法,冠词的用法:,什么是“冠”词?,冠词,The woman with a large haton her head isbeautiful.,冠词,顾名思义,就是戴在名词头上的一顶帽子。它是虚词,本身不能单独使用,只能附在一个名词上帮助说明这名词的含义。英语中冠词有两个,一是定冠词(the Definite Article),翻译成“这个”或“这些”;一是不定冠词(the Indefinite Article)译作“一个”或“一类”比如:我们说“书”用“book”是对的,但是,放在一个句子里,如:There is book on the desk.This is book I bought there.以上两句就是错句,a,the,定语从句,不定冠词的基本用法:1。用来表示“一”这个数量,意思和one差不多Eg:Rome was not built in a day.The work will be finished in a day or two.2。也可以用来表示“某一个”This poem was written by a peasant.A nurse is coming to see you.3.代表一类人或东西Even a child can answer this question.A horse is a useful animal.,4.在作表语的名词前加不定冠词的情形很多,主要说明某个人或东西属于哪一类。The man is an engineer.Is this a book or a magazine?5.用在一些固定搭配中和习惯用法中,要注意记忆!all of a sudden=suddenlyas a matter of fact=in factin a hurry at a time pay a visit toplay a trick on have a tryplay a joke on have a rest take a lookStudying English is a must.Its really a bargain.,a kind ofa sort ofa lot of=lots ofa number of=numbers ofa large quantity of=large quantities ofa great deal ofIt is a pleasure.=Its my pleasure.As a writer,he is a great success.The meeting proves to be a failure.You really gave me a surprise.What a pity/shame!,注意“a”和“an”a boy an houra hero an islanda useful tool an honest girla university an effective method元音音素发音的词前用“an”_European countryThere is _”s”in this word.There is _ silent“b”in this word.,a,an,a,使用定冠词的场合:,1。特指某些人和物Beijing is the capital of the PRC.2。指谈话双方都知道的人和物Please open the door.3。指前文中提到的人和事I met a girl yesterday.The girl is a nurse.4。用在世界上独一无二的事情或方位的名词前。The earth moves round the sun.,5.用在单数可数名词前,用来表示一类人或事。The tiger is in danger of dying out.The telephone was invented by Bell.6。用在序数词和形容词最高级前He directed the first and also the best film in his country.7。用在江河、湖泊、海洋、山脉和群岛的名称前the Yellow River the Pacific Ocean8。用在某些由普通名词和其它一些词组成的专有名词前:the Great Wall,9.用在姓氏的复数形式前,表示全家人或这一姓的夫妇二人the Turners the Greens the SmithsThe Lis10。在某些国名前the United States the United Kingdom11。在某些形容词前,表示一类人或事the poor/rich/dead/living/wounded12。表示朝代和年代的词前the Ming Dynasty in the 1980s13。在好多习惯用法中,in the morning/afternoon/eveningin the end in the beginningat the end of at the beginning ofIn the front of in the middle ofon the contrary on the other handIn the hope of,不用冠词的场合,1。在专有名词、物质名词和抽象名词前一般不用冠词:This kind of machine is made in China.Glass can be made into bottles.without hesitation/delay/mercy,2.在表示一类人或事物的复数名词前,一般不用冠词She likes reading stories.They are all teachers.Children like holidays.,3。名词前有物主代词、指示代词、不定代词或名词所有格时,不再用冠词Our country is a socialist one.-Have you any sister?-No,I have no sister.Peters brother is an engineer.,4。在节日、星期、月份、季节等名词前一般不用冠词但是在中国的传统节日前要用冠词National Day May DayNew Years Day Sunday spring Junethe Mid-autumn Festivalthe Spring Festivalthe Dragon-boat Festivalthe Lantern Festival,5。担任的头衔、职务的名词在句子中作表语、补语和同位语时,要省略冠词:Abraham Lincoln was elected President of the US.He is chairman of the meeting.Xiao Li,monitor of our class,often helps me.,比较:Water boils at 100CThe water in this well has been polluted.I like drinking tea.Long-jing is a wonderful tea.Coffee is served here.Id like three black coffees.Failure is the mother of success.The Asian Games is a great success.,在好多固定搭配中:husband and wife body and soulknife and fork day and nightafter school/class/workgo to hospital/work/school/prisonin front of at table on foot by car go to town out of question 在三餐饭,球类和棋类游戏名词前,goodbye,