too to enough to

so...that,too...to 和enough to的转换 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，并经常成为考试热点，请看下面三道试题：1．The water was so dirty that we couldn't drink it．（同义句）The water was ____ dirty for us ____ drink2．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．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。

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 that he can't carry it．→The box is too heavy for him to carry．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。

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 carry it．→The box is light enough for the child to carry． 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。

如： The man is so old that he can't go to work．→The man isn't young enough to go to work．=The man is too old to go to work.The desk is so heavy that I can't carry it．→The desk isn't light enough for me to carry．=The desk is too heavy for me to carry.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练习题：1.He is so young that he can’t go to school. (改为同义句)He is _______________________ go to school .(too … to)He is _________________________ go to school.(enough….to)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。

)3.My grandfather is too old to travel around. (改为同义句)My grandfather is _______ old _______ he ________________ travel around 。

4.My brother was so clever that he could work out the problem. (改为同义句) My brother __________________________ work out the problem.5The box isn’t light enough for him to carry. (改为同义句)The box ________________________ for him ________ carry.6He 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.7.The water was so dirty. We can’t drink it. (改为同义句)The water was too __________________________________ .6.The water in this river is very dirty. Fishes can’t live in it.The water in this river is ____________ that fishes ___________ in it.7.My brother got up late yesterday. He was late for school.My brother got up ________ that_____________________8.The boy was too young to go to school.(同义句The boy was________young__________he_________go to school.9.He is so strong that he can lift the heavy stone.（以下题都改为同义句He is __________ __________ __________lift the heavy stone.10.He got up early so that he could catch the first bus.He got up early _____________________ catch the first bus.11.He works very hard so that he can pass the exam.He works very hard_________________pass the exam .12.Tom didn’t come to school last week because he was ill.Tom didn’t come to school last week ________________ his illness.13.It was raining hard so the sports meeting will be put off._________ it was raining hard , the sports meeting will be put off..____________the heavy rain, the sports meeting will be put off..14.The old man was so angry that he couldn’t say a word.The old man was__________angry _________ ________a word.15.Although flying is exciting,it isn’t dangerous.Flying is exciting, ________ it isn’t dangerous.16.She was very tired, but she went on working.________ was very tired, she went on working.17.The lazy boy got up after 8 o’clock this morning.The lazy boy_________ __________up_______8 o’clock this morning.18.When the boy was 4 years old,he could paint Chinese painting.He could paint Chinese painting._________ __________ __________ __________4.1.A: He is old enough to join the army.B: He is __________ old ___________ he can join the army.2. A: He is too young to go to school.B: He is ___________ old ___________ _________ go to school.3. A: The problem is so difficult that I can't work it out.B: The problem isn't _________ __________ ___________ ___________ to work out.4. A: The bag is too heavy for her to carry.B: The bag is __________ heavy ___________ __________ can't carry __________ .5. A: This pair of shoes is so dirty that nobody will wear it.B: This pair of shoes is too dirty ___________ ___________ to wear.6: A: He isn't tall enough to join the team.B: He is __________ __________ __________ join the team.7. A: I am very glad to do it for you.B: I am __________ __________ glad to do it for you.8. A: She hasn't enough time to do the work.B: She has ________ ________ time to do the work.。