分?jǐn)?shù)的概念：

一般情況下，表示分?jǐn)?shù)時，分子要用基數(shù)詞，分母用序數(shù)詞(first, second, third ...)。如果分子大于1，分母必須用復(fù)數(shù)形式。

分?jǐn)?shù)的表示法：

分?jǐn)?shù)由基數(shù)詞和序數(shù)構(gòu)成—分子用基數(shù)詞，分母用序數(shù)詞，分子超過“1”時，分母用復(fù)數(shù)：
如：a[one] sixth 六分之一
two thirds 三分之二
three fifths 五分之三
注：
（1）1/2 通常讀作a[one] half，一般不讀作a second。
（2）1/4 可讀作a[one] fourth，也可讀作a[one] quarter。
（3）分子超過“1”分母之所以用復(fù)數(shù)可以這樣理解：“三分之二”即兩個(two)三分之一(third)，既然是兩個“三分之一”，那“三分之一”當(dāng)然要用復(fù)數(shù)，即用thirds。
（4）在數(shù)學(xué)上，為了簡潔起見，分子和分母均可用基數(shù)詞，其間用介詞over：3/4讀作three over four(對于比較復(fù)雜的分?jǐn)?shù)通常采用此讀法)
（5）帶分?jǐn)?shù)的讀法：在整數(shù)與分?jǐn)?shù)之間用and連接：five and two thirds

分?jǐn)?shù)在句中的作用：

1、主語：
如：A quarter of the population voted for him. 四分之一的人投他的票。
The other third of the black population live in poverty. 另外三分之一的黑人生活在貧困之中。
Three-fifths of the computers on display were home-made. 展出的電腦五分之三是國內(nèi)生產(chǎn)的。
2、賓語或介詞賓語：
如：Mother divided the cake into thirds. 媽媽把蛋糕分成三份。
Give a quarter of the pie to each of them. 給他們每人四分之一塊餡餅。
They account for one-senventh of the population. 他們占人口的七分之一。
3、表語或同位語：
如：The crop that year was only one-third of the usual amount. 那年的收成只是常年產(chǎn)量的三分之一。
Over twelve million people, about three-fifths of the local population are Hans. 有一千二百多萬人是漢人，約占當(dāng)?shù)厝丝诘奈宸种�三�?BR>4、定語：
如：It's one-twentieth the thickness of a human hair.它相當(dāng)于人的頭發(fā)絲二十分之一那么細。
The mass of an electron is1/850 that of a hydrogen atom. 電子的質(zhì)量相當(dāng)于氫原子質(zhì)量的1/850。
It produces power at 1/8 the cost in a thermal power plant. 它的發(fā)電成本只是熱電廠成本的八分之一。
5、狀語：
如：China is one-sixth larger than the United States. 中國比美國大六分之一。
This substance reacts one-tenth as fast as the other one. 這種物質(zhì)的反應(yīng)速度只是另一種物質(zhì)的十分之一。

百分?jǐn)?shù)的表示法：

百分?jǐn)?shù)由基數(shù)詞（或小數(shù)）和百分號（%）組成，百分號（%）讀作percent：
如：fifteen percent(15%),
(zero)point six percent(0.6%)
注：百分?jǐn)?shù)后接名詞時有時用介詞of，有時不用：
如：30% of the students (30%的學(xué)生)
a 30% chance (30%的把握)
兩者的區(qū)別是：后接介詞of時，percent為名詞，of表示整體中的部分；不接介詞of時，percent為形容詞(此時不表示整體與部分的關(guān)系)。
如：6 percent of the interest＝利息中的百分之六
at 6 percent interest＝按百分之六的利息。
注：當(dāng)百分?jǐn)?shù)、分?jǐn)?shù)后面加名詞或代詞時，要根據(jù)這個名詞或代詞來決定其謂語動詞的單復(fù)數(shù)形式。如果是復(fù)數(shù)名詞或代詞，謂語動詞用復(fù)數(shù)；如果是單數(shù)名詞（或不可數(shù)名詞）或代詞，謂語動詞用單數(shù)。

相關(guān)高中英語知識點：主謂一致

主謂一致的概念：

謂語的數(shù)必須和主語的人稱和數(shù)保持一致，這就叫主謂一致。

主謂一致的基本原則：

1)語法一致原則，即在語法形式上取得一致。例如，主語是單數(shù)形式，謂語動詞也采取單數(shù)形式；主語是復(fù)數(shù)形式，謂語動詞也采取復(fù)數(shù)形式。
例如：The students are very young.
This picture looks beautiful.
2)意義一致原則，即從意義著眼處理一致關(guān)系。例如，主語形式雖是單數(shù)但意義是復(fù)數(shù)，謂語動詞也采取復(fù)數(shù)形式；
而有些主語形式雖是復(fù)數(shù)但意義上看作單數(shù)，謂語動詞也采取單數(shù)形式。
例如：The people in that country are fighting for independence.
The crowd deeply respect their leader.
Three years in a strange land seems a long time.
3)就近原則，即謂語動詞的單數(shù)或復(fù)數(shù)形式取決于最靠近它的詞語。
例如：Neither hen or I am going to see the film tonight because we are busy.

幾對容易混淆詞組的一致用法：

1、由“this／thatkind／typeof+名詞”作主語，謂語動詞用單數(shù)形式；而由"these／thosekind／typeof+復(fù)數(shù)名詞”作主語，謂語動詞用復(fù)數(shù)形式。
例如：This kind of apples is highly priced.
Those kind(s) of tests are good.
2、由“a number of，a totalo f，an average of+復(fù)數(shù)名詞”作主語，謂語動詞用復(fù)數(shù)形式；由“the number of，the total of，the average of+復(fù)數(shù)名詞”作主語，謂語動詞用單數(shù)形式。
例如：A number of students are waiting for the bus.
The number of the students in this university is increasing yearly.
3、one of，the(only) one of的一致用法
例如：This is one of the books that have been recommended.
This is the(only) one of the books that has been recommended.

主謂一致用法點撥：

1、并列結(jié)構(gòu)作主語謂語用復(fù)數(shù)：
如：Reading and writing are very important.
注意：當(dāng)主語由and連結(jié)時，如果它表示一個單一的概念，即指同一人或同一物時，謂語動詞用單數(shù)，and此時連接的兩個詞前只有一個冠詞。
如：The iron and steel industry is very important to our life.
典型例題：
The League secretary and monitor___asked to make a speech at the meeting.
A. is
B. was
C. are
D. were
答案：B.
注：先從時態(tài)上考慮。這是過去發(fā)生的事情應(yīng)用過去時，先排除A、C本題易誤選D，因為The League secretary and monitor 好象是兩個人，但仔細辨別，monitor前沒有the，在英語中，當(dāng)一人兼數(shù)職時只在第一個職務(wù)前加定冠詞。后面的職務(wù)用and相連。這樣本題主語為一個人，所以應(yīng)選B。

2、主謂一致中的靠近原則：
1）當(dāng)there be句型的主語是一系列事物時，謂語應(yīng)與最鄰近的主語保持一致。
例如：There is a pen, a knife and several books on the desk.
There are twenty boy-students and twenty-three girl-students in the class.
2）當(dāng)either…or…與neither…nor，連接兩個主語時，謂語動詞與最鄰近的主語保持一致。
如果句子是由here, there引導(dǎo)，而主語又不止一個時，謂語通常也和最鄰近的主語一致。
例如：Either you or she is to go.
Here is a pen, a few envelops and some paper for you.

3、謂語動詞與前面的主語一致：
當(dāng)主語后面跟有with, together with, like, except, but, no less than, as well as等詞引起的短語時，謂語動詞與前面的主語一致。
例如：The teacher together with some students is visiting the factory.
He as well as I wants to go boating.

4、謂語需用單數(shù)：
1）代詞each和由every, some, no, any等構(gòu)成的復(fù)合代詞作主語，或主語中含有each,every,謂語需用單數(shù)。
例如：Each of us has a tape-recorder.
2）當(dāng)主語是一本書或一條格言時，謂語動詞常用單數(shù)。
例如：The Arabian Night is a book known to lovers of English.
3）表示金錢，時間，價格或度量衡的復(fù)合名詞作主語時，通常把這些名詞看作一個整體，謂語一般用單數(shù)。(用復(fù)數(shù)也可，意思不變。)
例如：Three weeks was allowed for making the necessary preparations.
Ten yuan is enough.

5、指代意義決定謂語的單復(fù)數(shù)：
1）在代詞what, which, who, none, some, any, more, most, all等詞的單復(fù)數(shù)由其指代的詞的單復(fù)數(shù)決定。
例如：All is right. (一切順利。)
All are present. (所有人都到齊了。)
2）集體名詞作主語時，謂語的數(shù)要根據(jù)主語的意思來決定。
例如：family, audience, crew, crowd, class, company, committee等詞后用復(fù)數(shù)形式時，意為這個集體中的各個成員，用單數(shù)時表示該個集體。
例如：His family isn't very large. 他家不是一個大家庭。
His family are music lovers. 他的家人都是音樂愛好者。
但集合名詞people, police, cattle, poultry等在任何情況下都用復(fù)數(shù)形式。
例如：Are there any police around?
3）有些名詞，如variety, number, population, proportion, majority等有時看作單數(shù)，有時看作復(fù)數(shù)。
A number of+名詞復(fù)數(shù)+復(fù)數(shù)動詞。 The number of+名詞復(fù)數(shù)+單數(shù)動詞。
例如：A number of books have lent out.
The majority of the students like English.

6、與后接名詞或代詞保持一致：
1）用half of, part of, most of, a portion of等詞引起主語時，動詞通常與of后面的名詞，代詞保持一致。
例如：Most of his money is spent on books.
Most of the students are taking an active part in sports.
2）在一些短語，如many a或more than one所修飾的詞作主語時，謂語動詞多用單數(shù)形式。
但由more than…of作主語時，動詞應(yīng)與其后的名詞或代詞保持一致。
例如：Many a person has read the novel. 許多人都讀過這本書。
More than 60percent of the students are from the city. 百分之六十多的學(xué)生都來自這個城市

主謂一致知識體系：

主謂一致用法拓展：

1）當(dāng)everyone，everybody，noone，nobody，anyone，anybody，someone，somebody，everything，anything，something，nothing等用作主語時，其相應(yīng)的代詞一般用單數(shù)形式。
例如：If anybody calls, tell him that I'm out.
Something strange happened, didn't it?
2）人稱代詞與名詞的呼應(yīng)：人稱代詞I(me)，he(him)，she(her)，it(it) 都是代替前面的單數(shù)名詞，而they(them)，we(us)則是代替復(fù)數(shù)名詞的，you既可以代表單數(shù)，也可以代表復(fù)數(shù)。但表示泛指的時候，用he或one來表示。
例如：If a young person enters a classical music field only for money, he is in the wrong profession.
3）物主代詞與名詞的呼應(yīng)：my，our，his，her，its，their要與代替的名詞在數(shù)上一致。
例如：The welfare department，as well as the other social services，will have its budget cut.
4）反身代詞與其所代成分間的呼應(yīng)。
例如：Many primitive people believed that by eating ananimal they could get some of the good qualities of that animal for themselves.
5）指示代詞與所代名詞間的呼應(yīng)：this和that指代單數(shù)名詞或不可數(shù)名詞，these和those指代復(fù)數(shù)名詞(those還可以用作先行詞，引導(dǎo)定語從句，表示“那些人”)。
例如：She invited all those who had been her former colleagues.
6）much和muchof后接不可數(shù)名詞，而many和manyof后接可數(shù)名詞的復(fù)數(shù)。
例如：There is not much coal left.
A great many of the houses were knocked down by the earthquake.
7）表示量的詞后面有的接可數(shù)名詞，有的接不可數(shù)名詞。
接可數(shù)名詞的有：a number of，a rangeof，a series of十復(fù)數(shù)名詞；
接不可數(shù)名詞的有：a great deal of，an amount of十不可數(shù)名詞；
既可接可數(shù)又可接不可數(shù)名詞的有：a lot of，a variety of。
例如：1.The government attached a great deal of importance to education.
2.Quiteanumberofwomenappliedforthisjob.
3.The college library has avariety of books.
4.An apple is avariety off ruit.

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