too..to...和not..enough to..的用法

too …to …. ; not …enough to…

Step 1 看图说话利用课本P36页的图画和提示词练说too…to do 和not … enough to do 句子。如：1. The snake / dangerous/ hold . / The boy not brave

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

板书too…to do 和not … enough to d o并让学生明确这两个短语的中文意思是“太… 而不能…”。提醒学生观察这两个句子结构中的形容词用什么形式，to do中的do 可否变换形式。在准确理解的基础上继续看图说话。

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

板书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)