4.“二十”以上的多位数，个位数用序数词，其余仍用基数词。

ninety-third　　　　　　 one hundred and forty-ninth

3.不规则的序数词有以下几个：first，second，third，fifth，eighth，ninth，twelfth

2.以ty结尾的基数词构成序数词时，先把y改成i，再加eth。如：the twentieth，the fiftieth

1.序数词一般由基数词后+th构成，前面一般加定冠词the，表示“第几”

the two hundredth，the eighteenth

加不定冠词，则意为“又一,再一”.

I like the film very much, so I want to see it a second time.

4.dozen和score的复数形式应注意以下几点：

①dozen表示：一打，十二个，score表示：二十；

②当dozen与数词，或many，several等连用时，不加“s”，所修饰的名词前常省去“of’；score则不然。

two dozen pencils两打铅笔

two score of pencils四十支铅笔

dozens of people=scores of people许多人

③当后面的名词前有"these"，“those"，“them"，" us"等词时, dozen后应加"of "。

a dozen of these people

two dozen of them

three score and ten people中不加of(七十人)

3.基数词hundred，thousand，million，billion表示确切数目时不能加s

five thousand students (五千个学生)

但在表示不确切数目时，要用复数形式，如：hundreds of／thousands of students(许多学生)

2.101-999的三位数由hundred加and再加两位数或末位数。

three hundred and twenty-five (325)

1.21-99的两位数，在十位数和个位数之间加连字符构成。如：fifty- three (53)

7.it的用法

①用作人称代词,代替前文提到的事情。

This bike is not mine. It’s Peter’s.

②用以代替提示代词this, that

-What is this?　　　　　 　-It’s a pen.

-Whose book is that?　　　 -It’s Mike’s.

③起指示代词的作用,指一个人或事物

-Who is knocking at the door?　　　 -It’s me.

-Who is making such a noise.　　　 -It must be the children.

④指环境情况等。

It was very quiet at the moment.

⑤指时间，季节，天气，气候等

-What time is it?　 　　　-It is eight o’clock.

It often rains in summer.

⑥指距离

It is five kilometers from the office to my home.

It is a long way to the factory.

⑦作形式主语和形式宾语

当动词不定式,动名词或从句作主语时,通常把它们放在谓语之后,而用it作句子的形式主语

It is not easy to finish the work in two days.

It is not a good habit to stay up late.

It is no use crying over split milk.

It is a pity that you didn’t read the book..

当复合宾语中的宾语是不定式,动名词,宾语从句时,往往把宾语放在它的补足语后面,而用it作形式宾语,放在宾语补足语之前

I think it no use arguing with him.

I found it very interesting to study English.

He made it clear that he was not interested in this subject.

注意：see to it that…(务必)和take it for granted that…(想当然)句型中的it，以及词组make it

中的it(做事成功，搞定)。

⑧用于强调结构(详见专题九)

要强调句子的某一部分(通常是主语,状语,宾语), 可以把it 当作先行词.这种句子的结构是 “It is(was)+被强调部分+that (who )+句子的其余部分” .如果强调的部分是人,可用who whom 代替that

I met an old friend in the park yesterday.

此句各部分被强调后句型如下：

It was I who /that met an old friend in the park yesterday.

It was an old friend who/ that/whom I met in the park yesterday.

It was in the park that I met an old friend yesterday.

It was yesterday that I met an old friend in the park.

(二)数词

数词分两类：基数词和序数词

6.不定代词

不定代词种类较多,在使用时应注意其用法与区别。为了便于记忆我们择其重点以表格的形式列出。