too …to …. ; not …enough to…

The snake is too dangerous to hold. The boy is not brave enough to hold it .

too…to do 和not … enough to do 的中文意思是 “太… 而不能…”。

 

用下列词语造句（使用too...to do...或not...enouth to do结构）

2. The girl / short / get on the elephant. / she / not / tall .

3. The elephant / heavy / carry. / The boy / not strong.

4. The elephant / fat / go through the gate. / The gate / not wide.

5. The monkey / far away / get the bananas. / The bananas / not near.

6. The cat/ slow/ catch the bird./ It / cannot run/ fast .

Step 2 抛砖引玉

The snake is too dangerous to hold. The boy is not brave enough to hold it . (改为同义句)

The snake is so dangerous that the boy _________ hold it.

学生在理解的基础上探求答案，在探求答案的过程中获得新知。

板书 so … that + 含有can’t / couldn’t do的否定句等同于too…to do…; not …enough to do

同步操练：1. The girl is too short to get on the elephant. (改为同义句)

 ①The girl______________________ to get on the elephant.

②The girl ____________that she ___________ get on the elephant.

 ③The elephant is so tall__ that the girl can’t get on it .

④The elephant _________ enough ______ the girl ______ get on.

⑤The elephant __________tall ______ the girl _______ get on.

完成句子后求异：

①与原句比较后发现：由too… to do… 结构转换为not … enough to do 结构时，要找到句中形容词的反义词。

③与④比较后发现：so… that + 含有can’t / couldn’t do的否定句结构的句子，若主从句的主语不一致时，改写为too… to do… 或not … enough to do …结构时, 要在不定式to do前添for sb ，若主从句的主语一致，则不须添for sb。如：

 He is so young that he can’t go to school. (改为同义句)

He too young to go to school .

He not old enough to go to school.

观察④ 、⑤ 两句可得：在too… to do… 或not … enough to do …的句子中，若to do 的宾语与句子的主语相一致时，须省略it。  发散思维：若把句子改为过去时，应该怎么办？

1. The girl was too short to get on the elephant. (改为同义句)

The elephant was so tall__ that the girl couldn’t get on it .

2. He ran very fast. He couldn’t stop.

  He ran too fast to stop.

  He ran so fast that he couldn’t stop. (方法是句型转换时要注意时态一致。)

Step 3 链接中考

The panda is so fat that it can’t go through the hole.(改写为同一意思的句子)

The hole ________________________________  such a fat panda to go through.

The ice on the lake was so thin that people couldn’t skate on it. (改写为同一意思的句子)

The ice on the lake was not _______ enough _______ people ____________________.

Mr. King is very busy at work. He can’t take a holiday.(改为同义句)

Mr. King is ______________________ take a holiday.

My grandfather is too old to travel around. (改为同义句)

My grandfather is _______ old _______ he ________________ travel around any __________.

Step 4 巩固练习

1.     My brother was so clever that he could work out the problem. (改为同义句)

My brother __________________________ work out the problem.

2.     The box isn’t light enough for him to carry. (改为同义句)

The box ________________________ for him  ________ carry.

3.     He is very short . He can’t reach the book on the shelf.(合并为一句)

He is ________________________ reach the book on the shelf.

4.     The water was so dirty. We can’t drink it. (改为同义句)

The water was too __________________________________ .

5.     The water in this river is very dirty. Fishes can’t live in it.

The water in this river is ____________ that fishes ___________ in it.

6.     My brother got up late yesterday. He was late for school.

My brother got up ________ that

so．．．that，too．．．to和enough to是初中英语教材中的重要结构。在一定条件下它们可以相互转换，并经常成为中考热点，请看下面三道中考试题：

1．The water was so dirty that we couldn't drink it．

 

The water was ____ dirty for us ____ drink．

 

2．The child is so young that he can't put on his clothes．

 

The child isn't ____ ____ ____ put on his clothes．

 

3．The problem is too difficult for me to work out．

 

The problem isn't ____ ____ ____ for me to work out．

 

由分析可知答案为：1．too，to 2．old enough to 3．easy enough

 

那么在什么情况下三者可以相互转换呢？根据其结构特点我们可以看出：

一、so．．．that与too．．．to的转换

 

当that引导的从句为否定式时，从句主语与主语的主语相同时，so．．．that可转换为too．．．to结构；若从句主语与主句的主语不相同时，so．．．that可转换为too．．．for sb．to结构。例如：

 

He is so young that he can't go to school．→ He is too young to go to school．

 

The box is so heavy thathe can'tliftit．→The box is too heavy for him to lift．

 

二、so．．．that与enough to的转换

 

1．当that引导的从句为肯定式时，若从句主语与主句主语相同时，so．．．that可转换为 enough to结构；若从句主语与主句主语不相同时，so．．．that可转换为enough for sb．to结构。例如：

 

Tom is so old that he can go to school．→Tom is old enough to go to school．

 

The box is so light that the child can liftit．→The box is light enough for the child to lift．

 

2．当that引导的从句为否定式时，若从句主语与主句主语相同时，so．．．that可转换为enough to的否定结构；若从句主语与主句主语不相同时，so．．．that可转换为 enough for sb．to的否定结构。注意：转换后的形容词（副词）要用其相应的反义词。例如：

 

The man is so old that he can't go to work．→The man isn't young enough to go to work．

 

The desk is so heavy that I can't moveit．→The desk isn't light enough for me to move．

 

三、enough to的句式为否定式时，enough to可以转换为too．．．to结构。但转换后的too．．．to结构中的形容词（副词）要用其相应的反义词。例如：

 

He is not old enough to do the job．→He is too young to do the job．

 

Tom didn't walk slowly enough for us to keep up with him．→Tom walked too fast for us to keep up with him．

主语+谓语v.+too+adj/adv(for sb)+to do ???

主语 +谓语v.+adj/adv+enough(for sb)+to do ??

主语+谓语v.+so+adj/adv(for sb)+that ??从句

变换下列句型：

1. a. The box is so heavy that I can't carry it.

b. The box is ________ heavy______ ________ ________ carry.

c. The box is not ________ ________ for me to carry.

2. a. The maths problem isn't easy enough for me to work out.

b. The maths problem is ________ difficult ________ I can't work it out.

c. The maths problem is ________ difficult ________ ________ ________ work out.

3. a. The book is interesting enough for　everybody to read.

b. The book is ________ interesting________ everybody likes to read　it.