问题补充：
Li Na is famous all the tennis fans in China know her.
A. too; to
B. enough ; to
C. as; as
D. so; that
答案：
A. too; to
B. enough ; to
C. as; as
(答案→)D. so; that
解析：句意：李娜是如此著名以致于所有在中国的网球迷都认识她。
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。
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 go to school．→ He is too young to go to school．
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．
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 go to work．→The man isn young enough to go to work．
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 walk slowly enough for us to keep up with him．→Tom walked too fast for us to keep up with him．
故选D
