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．

ｔｏｏ…ｔｏ…结构

经典考题：

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．

4. The book is interesting enough for everybody to read. 
      The book is _____ interesting _____ everybody likes to read it.
    5. The boy is so short that he can't reach the buttons of the lift.
        The boy is _____ short _____ _____ the buttons of the lift.
       The boy isn't _____ _____ _____ _____ the buttons of the lift.

6. He is old enough to go to school.
         He is _____ _____ that _____ _____ go to school.
     7. She was so weak that she couldn't take care of her baby.
         She was _____ weak _____ take care of her baby.

Keys：

1．too，to 2．old enough to 3．easy enough 4. so; that 5. too; to reach; tall enough to reach   6. so old; he can 7. too; to