編/淺茉輕語
一擂找、數(shù)詞的定義
表示數(shù)目多少或順序多少的詞叫數(shù)詞，數(shù)詞分為基數(shù)詞和序數(shù)詞囊扳。
表示數(shù)目多少的數(shù)詞叫基數(shù)詞吩翻；
表示順序的數(shù)詞叫序數(shù)詞。
二锥咸、基數(shù)詞
1.基數(shù)詞的構(gòu)成
1）1-20
one,two,three,four,five,six,seven,eight,nine,ten,eleven,twelve,thirteen,fourteen,fifteen, sixteen, seventeen, eighteen, nineteen, twenty
2）21-99 先說“幾十”狭瞎，再說“幾”，中間加連字符搏予。
23→twenty-three,34→thirty-four,
45→forty—five,56→fifty-six,
67→sixty-seven,78→seventy-eight,
89→eighty-nine,91→ninety-one
3）101—999先說“幾百”熊锭，再加and,再加末兩位數(shù)或末位數(shù)；
586→five hundred and eighty-six
803→eight hundred and three
4）【重點(diǎn)】
l,000以上,先從右往左數(shù)雪侥，每三位數(shù)加一個(gè)“,”,第一個(gè)“,”前為thousand.第二個(gè)“,”前為million,第三個(gè)“,”前為billion（美式）或thousand ,million（英式）,然后一節(jié)一節(jié)地表示碗殷。
1,001→one thousand and one
9,785→nine thousand, seven hundred and eighty-five
18,423→eighteen thousand, four hundred and twenty-three
6,260,309→six million two hundred and sixty thousand three hundred and nine
【注意美式和英式的區(qū)別】
750,000,000,000→seven hundred and fifty, billion（美式）
億
seven hundred and fifty thousand million（英式）
2.基數(shù)詞的用法
1）作主語
eg.Four Of them come from Paris.
2）作賓語
eg.一 How many books would you like？
一I would like two.
3）作表語
eg.Seven minus two is five.
4）作定語
eg.There are three people in my family?
5）作同位語
eg. You two will go swimming with us.
6）表具體數(shù)時(shí),hundred, thousand ,million用單數(shù)速缨。
eg. There are six hundred students in our grade.
7）表不確定的數(shù)字時(shí),數(shù)詞用復(fù)數(shù)锌妻。
若帶名詞，再加of旬牲。 hundreds of（數(shù)百,成百上千的）,thousands of（數(shù)干,成千上萬的）,millions of（數(shù)百萬）two thousand (兩千)
Thousands and thousands of people have visited the city.成千上萬的人參觀了這座城市仿粹。
8）在一些表示“一排”或“一組”的詞組里；
eg,They arrived in two sand threes.
他們三三兩兩地來了原茅。
9）表示“…十”的數(shù)詞的復(fù)數(shù)可以表示人的歲數(shù)或年代吭历。
eg. He is in his early thirties.
他有三十來歲（31—34歲）：
This took place in the 1930s.
這事發(fā)生在二十世紀(jì)三十年代；
10）【重點(diǎn)】
表示時(shí)刻
鐘點(diǎn)表達(dá)法擂橘。
順讀法(鐘點(diǎn)＋分鐘)? ? 如：
4:30 four thirty
4:45 four forty-five?
4:15 four fifteen? ?
倒讀法(分鐘＋to／past＋鐘點(diǎn))? ?
如：4:30 half past four
4:15
fifteen past four
a quarter past four?
4:45
fifteen to five
a quarter to five
eg.I watch CCTV News at seven o’clock every evening.
11）表示百分?jǐn)?shù)
百分?jǐn)?shù)的表達(dá)方式是：
基數(shù)詞+ percent（單數(shù)形式）+of+名詞晌区。如：
Thirty percent of the students in my class are from cities.? ? 我班30%的學(xué)生來自城市。
About 61 percent of the surface is covered by water.? ? 大約61%的表面被水覆蓋著。
12）小數(shù)的讀法
小數(shù)點(diǎn)讀作"point"朗若，小數(shù)后各位數(shù)要分別讀恼五， 小數(shù)點(diǎn)前的數(shù)若為"0"可略去不讀。
Examples：?
2.468 讀作：two point four six eight
0.157 讀作：（zero）point one five seven
II 序數(shù)詞
1.序數(shù)詞的構(gòu)成
（1）一般在基數(shù)詞后加th
eg.four→fourth,thirteen→thirteenth
（2）不規(guī)則變化
one→first, two→second, three→third, five→fifth,eight→eighth,
nine→ninth,twelve——twelfth
（3）以y結(jié)尾的十位整數(shù)捡偏，變y為ie再加th
twenty→twentieth, forty→fortieth, ninety→ninetieth
（4）從二十一后的“幾十幾”直至“幾百幾十幾”或“幾千幾百幾十幾”只將個(gè)位的基數(shù)詞變?yōu)樾驍?shù)詞唤冈。
twenty-first,two hundred and forty-fifth
2.序數(shù)詞的用法
（1）序數(shù)詞作定語時(shí)，一般要與定冠詞或物主代詞連用银伟。
eg.Tom is their second son.
He is the first one to come here.
（2）序數(shù)詞有時(shí)可與不定冠詞連用，表示數(shù)量上“又—”,“再一”
eg： He tried a second time.他又試了—次绘搞。
Shall l ask him a third time彤避？還要我再問他—次嗎？我已問了他兩次）
（3）序數(shù)詞的縮寫形式為：阿拉伯?dāng)?shù)字加上這個(gè)詞的末尾兩個(gè)字母夯辖。
1st 2nd,3rd,4th,20th,21st,22nd,23rd
（4）表示年琉预、月、日時(shí)蒿褂，年用基數(shù)詞圆米，日用序數(shù)詞。
2005年8月15日：
（英）15,8,2005=15th,August,2005啄栓；（美）8,15,2005=August 15th,2005
III基數(shù)詞和序數(shù)詞都可以用來給數(shù)字編號(hào)
The first lesson=Lesson Two（第二課）
第305房間：Room three o（零）five
長(zhǎng)安街76號(hào)：seventy-six Changan Street
電話號(hào)碼：
204-2244：
telephone number
two o（零） four two two（double two） four four
十一路公共汽車：Bus（No.） eleven
IV分?jǐn)?shù)詞的表達(dá)
分子用基數(shù)詞娄帖，分母用序數(shù)詞，分子大于1時(shí)昙楚，分母加s
eg.
1／3-one third近速；2／5-two fifths
V數(shù)學(xué)運(yùn)算的表達(dá)
eg.3+5=8 Three plus／and five is eight.
9-2=7 Nine minus two is seven.
6x5=30
Five times six is thirty ／six unutilized five is thirty.
8÷2=4 Eight divided by two is four.
VI倍數(shù)表示法
a. 主語+謂語+倍數(shù)（或分?jǐn)?shù)）+ as + adj. + as
I have three times as many as you. 我有你三倍那么多。
b. 主語+謂語+倍數(shù)（分?jǐn)?shù)）+ the size (amount堪旧，length…) of…
The earth is 49 times the size of the moon.
地球是月球的49倍削葱。
c. 主語+謂語+倍數(shù)（分?jǐn)?shù)）+ 形容詞（副詞）比較級(jí)+ than…
The grain output is 8 percent higher this year than that of last year.
今年比去年糧食產(chǎn)量增加8%。
d. 還可以用by+倍數(shù)淳梦，表示增加多少倍
The production of grain has been increased by four times this year.
今年糧食產(chǎn)量增加了4倍析砸。
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