意思不同：to：對(duì)于、為了、(表示方向)到、向、(表示間接關(guān)系)給；too：也、太、而且、很。用法不同：to：表示在某范圍之外，兩者之間可以互相連接，也可以不連接，可與表示“談話”“交際”的詞連用。to表示交際的動(dòng)作一般是單向的；too：用于肯定句，too通常位于句末，其前的逗號(hào)可有可無。

在英語中to的用法是比較重要的，一般來說 to 有兩種基本用法：

1.做介詞，表示“到，向，往”，如go to，fly to，后面跟名詞作定語，構(gòu)成介賓結(jié)構(gòu)。

2.動(dòng)詞不定式的標(biāo)志，很常見的，如：want to do，be happy to do。

注意有一些看似不定式但實(shí)為介詞的結(jié)構(gòu)，如 look forward to，pay attention to ，他們后面跟動(dòng)詞的ing 形式作賓語，千萬不能跟原形。

其他的如to +do 作定語等等基本都是以上兩種用法的延伸。

而to的用法重點(diǎn)主要是作介詞，下面講解to作為介詞的用法，大約有20多種

一：表示相對(duì)，針對(duì)

be strange (common, new, familiar, peculiar, distinct, sensitive,immune, vulnerable, indispensable) to

Air is indispensable to life.

Aircrafts are vulnerable to interference caused by radiation.

This injection will make you immune to infection.

二：表示對(duì)比，比較

1：以-ior結(jié)尾的形容詞，后接介詞to表示比較，如：superior ,inferior,prior,senior,junior

The quarrel happened prior to my arrival.

2: 一些本身就含有比較或比擬意思的形容詞，如equal，similar，equivalent，analogous

A is similar to B in many ways.

3：表示一些先后順序的形容詞，如：second,subsequent,next,preliminary,preparatory

Subsequent to the war,they returned to their hometown.

4: to也偶爾出現(xiàn)在個(gè)別動(dòng)詞之后,與動(dòng)詞形成固定詞組,表示比較,如:prefer to,compare to,incontrast to

compare to sth.表示比喻或比擬,而compare with sth.表示比較,如:

World is usually compared to a stage

Compared with his past,he has changed a lot.

Prefer的正確句型是:prefer A to B或prefer doing A to doing B,但當(dāng)prefer后接動(dòng)詞不定式時(shí),表示比較的介

詞to就要改成rather than ,如:

The undaunted soldier preferred death to surrender.

Many people prefer spending money to earning money.

They prefer to pursue careers rather than remain home as house wives.

5: to與及個(gè)別的名詞構(gòu)成比較之意,如:alternative

Going to an under water concert is a great alternative to going to dinner.

三: 表示修飾關(guān)系

1: 表示回復(fù),反應(yīng)意思的詞,如:answer to question,

solution to problem,response to inquiry,reaction to proposal,reply to letter

2: 表示建筑構(gòu)件的詞匯,如: entry,entrance,approach,access,passage,exit,vent,path

the approach to a bridge引橋

the approach to science

Half of the population was estimated to have no access to the health service.

The access to education 接受教育的機(jī)會(huì)

The access to medical care 享受公費(fèi)醫(yī)療的權(quán)利

3: 表示人物職位和官銜的詞,如:assistant to manager, ambassador to Spain, successor to tradition,heir to

throne,deputy to the National People’s Congress

advisor to the Prime Minister

1、too一般放于肯定句末,表示“也”。例如：

I know the answer,too.我也知道答案。

注意：否定句末的“也”須用either.

I don know the answer,either.我也不知道答案。

2、too有時(shí)可放在句首以便引人注目,達(dá)到強(qiáng)調(diào)的目的。

Too,the reader will find in this book many interesting pictures.

讀者也會(huì)在這本書中 發(fā)現(xiàn)許多有趣的圖片。

3、在第二次否定時(shí),可用also或too代替以加強(qiáng)主語的語勢(shì),但其必須放于否定詞前。

4、固定句式 too ---- to 太---而不能

The books are too heavy to carry.這些書太重了，搬不動(dòng)。