it和that区别?详细的有实例!

这与主语从句和宾语从句的用法有关：

主语从句与宾语从句两者的用法和在句中的作用是不同的，下面从它们的各自用法，介绍：

一．主语从句

主语从句 定义:在句子中担当主语的是一个从句,这个从句就叫做主语从句。

主语从句是在复合句中充当主语的从句，通常放在主句谓语动词之前或由形式主语it代替，而本身放在句子末尾。

1. It 作形式主语和it引导强调句的比较

It 作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化。而it引导的强调句则是对句子某一部分进行强调，无论强调的是什么成分，都可用连词that。被强调部分指人是也可用who/whom。例如：

It is a pity that you didn’t go to see the film.

2. 用it 作形式主语的结构

(1) It is ＋名词＋从句

It is a fact that … 事实是…

It is an honor that …非常荣幸

It is common knowledge that …是常识

(2) it is ＋形容词＋从句

It is natural that… 很自然…

It is strange that… 奇怪的是…

(3) it is ＋不及物动词＋从句

It seems that… 似乎…

It happened that… 碰巧…

(4) it ＋过去分词＋从句

It is reported that… 据报道…

It has been proved that… 已证实…

3. 主语从句不可位于句首的五种情况

(1) if 引导的主语从句不可居于复合句句首。

(2) It is said , (reported) …结构中的主语从句不可提前。例如：

It is said that President Jingo will visit our school next week.

(3) It happens…, It occurs… 结构中的主语从句不可提前。例如：

It occurred to him that he failed in the examination.

(4) It doesn’t matter how/whether …结构中的主语从句不可提前。例如：

It doesn’t matter whether he is wrong or not.

(5) 含主语从句的复合句是疑问句时，主语从句不可提前。例如：

Is it likely that it will rain in the evening?

4. What 与that 在引导主语从句时的区别

What 引导主语从句时在句时在从句中充当句子成分，如主语．宾语．表语，而that 则不然。例如：

What you said yesterday is right.

二：宾语从句的几个特征：1、引导词：what\which\whose\when\whether\if\where

2语序：宾语从句必须是用陈述语句。

如：I think that you must work harder.

宾语从句的引导词、连接词的区别、否定转移等现象。

(1)表达时间的几个句型：一般用when或者是what time：

What time will the train leave?

由于时刻都是固定的，也可以用一般现在时代替一般将来时：

What time does the train leave?

(2)时间的表达方式：8：19(nineteen past eight),7:57(three to eight)，在时间的中间也可以加上分的单词(minutes)

(3)had better +动词原型。意思是提要求，建议。但是上下级不能用这种方式，因为语气太重：

You had better give up smoking .

(4)sb leave sth +地点

I left my book in my classroom yesterday.

(5)may I have your name(address\age)?一般询问对方的年龄、名字等，不要习惯以前的问法，这样很不礼貌，而是要采访上面的问法。以前的习惯是：how old are you? \what's your name?

(6)修饰名词的代词次序：限-描-大-形---年---颜----籍----物--------类+名词：

this is a bridge.

This is a beautiful bridge

it/one/that

的用法和区别

I.

it／one

／that三者均可用作代词,

指代前面提到的名词。一般说来,

it指代同名同物;

one与that则指代同名异物。

I

have

lost

my

umbrella;

I'm

looking

for

it.

（该句中it就是指前面的my

umbrella）

I

have

lost

my

umbrella;

I

think

I

must

buy

one.

（one在该句中表泛指,

因为my

umbrella已经丢了）

The

umbrella

you

bought

is

cheaper

than

that

I

bought.

（替代词that在该句中特指“the

umbrella

I

bought”,

以区别“the

umbrella

you

bought”）

II.

one与that虽可用来指代同名异物,

但one为泛指,

相当于a／an＋名词;

that为特指,

相当于the

＋名词。所以one所指代的名词的修饰语一般为

a／an

／some

／any;

that所指代的名词的修饰语往往是the

／this

／that。

A

chair

made

of

steel

is

stronger

than

one

made

of

wood.

（该句中one可以换成a

chair）

The

water

in

the

cup

is

hotter

than

that

in

the

pot.

（该句中that可以换成

the

water）

III.

one只能代替可数名词单数,

代替可数名词复数时用ones;

that既可以代替不可数名词也可以代替可数名词单数,

代替可数名词复数时用

those。

I

like

this

pen

more

than

that

one.

（one代替可数名词单数pen）

There

were

a

few

young

people

and

some

older

ones

in

the

house.

（ones代替可数名词复数people）

Mary's

handwriting

is

far

better

than

that

of

Peter.

（that代替不可数名词

handwriting）

These

pictures

are

more

beautiful

than

those.

（those代替可数名词复数

pictures）

IV.

one既可代替事物,

也可代替人,

that只能代替事物而不能代替人。有时可以用the

one或the

ones代替that或those。

The

one

／That

on

the

table

is

mine.

（该句中The

one代替事物,

并且也可以用That）

He

is

the

teacher,

the

one

who

is

loved

by

the

students.

（该句中the

one代替人,

不能用that）

He

advised

the

farmers

to

choose

the

best

seed-heads,

the

ones

／those

that

had

the

best

color.

（该句中the

ones代替事物,

并且也可以用those）

V.

one一般有前置修饰语,

有时也可有后置修饰语或不用修饰语。而

that不能有前置修饰语,

但可有后置修饰语。

Cook

was

a

strict

but

good

captain,

one

who

took

good

care

of

his

sailors.

The

water

in

the

well

is

cleaner

than

that

in

the

river.

VI.

it可以替代句中的不定式或从句等,

充当形式主语或形式宾语。one与that均无此用法。

It

is

known

to

everybody

that

the

moon

travels

around

the

earth

once

every

month.

I

found

it

hard

to

get

on

with

her.

VII.

it与that均可以替代上文全句的内容或部分内容,

而one

／ones则不可以。

He

has

saved

my

life;

I'll

never

forget

it.

（it代替第一分句）

Tom

is

painting

his

house.

I

am

told

he

does

it

every

four

years.

（it代替前面分句的部分内容painting

his

house）

Let's

say

we

meet

here

at

three

o'clock.

That

ought

to

give

you

time

to

buy

everything.

（That代替前面表述的内容）

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