数词1.定义与分类:数词是用来表示事物的数目和顺序的词,表示多少的词叫做基数词,onetwothreefour表示第几的词叫做序数词firstsecondthirdfourthfifthsixth等等。2.作用:主语宾语表语定语状语同位语ItissixtherearesixbookSixisokIwanttobuysixWesixalwaysgetupearlyatsix注意数次作定语的用法:数词+名词(单数)+形容词afive-yearoldgirl3.基数词的构成及其用法英语中最基本的基数词有:(2)其他基数词的构成1)21-99十位个位之间要加连词符号(-)2)101--999等三位数中十位数或个位数的前面加and.101onehundredandone513fivehundredandthirteen678sixhundredandseventy-eight3)1000以上的数要用计数逗点,从个位开始每个三位数加一个逗点。123456789101112onetwothreefourfivesixseveneightnineteneleventwelve13141516171819thirteenfourteenfifteensixteenseventeeneighteennineteen2030405060708090100twentythirtyfortyfiftysixtyseventyeightyninetyone(a)hundred2335101twenty-threethirty-fiveonehundredandone第一个逗点处是thousand第二个逗点是百万million第三个逗点处是十亿billion。1,0004,596,78618,458怎么读??怎么写??4)基数词常以单数出现但是当基数词用作名词时可有复数形式。Shehasgotthreefives数词hundredthousandmillion前面有数词时表示确数不用复数形式,但是其后接of短语所表示的一个约数时用复数形式。Threehundreddeskshundredsofdesks6)dozen表示一打(12个)和score(20个)也是一个量的单位,其前有具体的数字或者several修饰时也不可加s表示一个确数,但是当他们不与具体的数词或several连用的时候要用复数表示约数。Threedozenbooksdozensofbooks4.序数词的构成及其用法(1)一般序数词1000th→onethousandth,1000000th→onemillionth.,第703→thesevenhundredandthird,第5480→thefivethousandfourhundredandeightieth.1st2nd3rd4th5th6th7th8th9th10th11th12th※first※second※thirdfourthfifthsixthseventheighthninthtentheleventhtwelfth13th14th15th16th17th18th19ththirteenthfourteenthfifteenthsixteenthseventeentheighteenthnineteenth20th30th40th50th60th70th80th90th100thtwentieththirtiethfortiethfiftiethsixtiethseventietheightiethninetiethoneundredth21st22nd23rd35th101sttwenty-firsttwenty-secondtwenty-thirdthirty-fifthonehundredandfirst(2)两位以上的序数词仅个位数部分用序数词,其余部分仍用基数词。如:thirty-sixth,forty-fifth(3)使用序数词时一般加定冠词the.如:I’minthethirdgrade.(4)序数词前有不定冠词a表示再一又一的意思AsecondtimeathirdoneAftereatingtwocakes,heateathirdone.5.分数的构成和用法分子用基数词,分母用序数词,分子是1时分母用单数,分子是2时分母用复数。1/2可以用half表示,四分之一可以用quarter表示。读带分数时,先读整数部分,再读分数部分,中间用and连接。1/5→onefifth;2/3→twothirds;4/7→foursevenths;1/2→ahalf;1/4→aquarter;3/4→threequarters;50%→fiftyhundredths(fiftypercent).32⅜thirty-twoandthreeeighths6.小数的构成及用法整数与小数之间用小数点隔开,读小数时每位数字要单独读出,小数点读point0读zero。0.1zeropointone0.03zeropointzerothree2.25twopointtwofive14.163fourteenpointonesixthree注意:1)和带分数连用的名词用复数2)如果带分数的整数部分是1名词在带分数之后用复数,名词在1和分数之间时,名词要用单数。Oneappleandathirdoneandonethirdapples.3)与小数连用的名词,整数是零时名词用单数,其他情况名词要用复数。7.百分数的构成和用法5%5percent22%twenty-threepercent8.倍数的构成及其用法1)倍数的表达法2倍twicedouble3倍threetimestriple4倍及以上:基数词+times2)倍数比较的表达法aAbe数+as+原级adjadv+asBThisdeskisasbigasthatone.bAbe数+times+比较级+thanBThisdeskisthreetimesbiggerthanthatone.cAbe数times+the+n(lengthheightsizeweightbreadthvalue)ofBThisdeskisthreetimesthesizeofthatone.3)倍数增减的表达法increasegouprisegrowdecreasereducedropfallgodown等词后面+by表示增减了多少+to表示增建到多少Themembershaveincreasedby1,000.to1,000.9.每隔每逢的表达法Every+基数词+复数名词every+序数词+单数名词Everythreedayseveryfourthday每逢四天每隔三天10.数字运算的表达法加读andplus减读minus乘读times除读dividedby等于读equalsoneandoneequalstwotendividedbyfiveequalstwo11.时间的表达法(1)先说分钟后说点钟,几点过几分,分钟不超过30时用past几点差几分或差几分几点,差的分钟不超过30分钟时用to。Itisfivepastseven.Itistwentytofive.itisaquartertofive.(2)年月日地表达法:一般情况下先说月份,再说日期,最后说年份但亦有例外,并且日期要用序数词。1988年5月1日的表达法May1(st),1988,读法:Maythefirst,nineteeneighty-eight.1983nineteeneighty-three.1)年份的读法两位两位的读。2)公元前的年份后面加B.C公元后的年份后面加A.D221.B.Ctwotwenty-one199.A.DA.D.1993)年代用年份的阿拉伯数字后+’s或s构成1730’s或1730s十八世纪三十年代theseventeenthirties二十世纪六十年代中期themid1960's或s12.编号及电话号码的表达法编号既可以用序数词也可以用基数词:theTenthLessonLessonTenRoom321读法:roomthreetwoone13.某人几十岁和十几岁的表达法几十岁:In+one's+数词几十的复数形式Themanisinhisearlythirties.十几岁:in+one'steens