Question

too...to,not enough,so...that的区别和用法

Answer 1

too... to...(太......以至于不......)是个简单句，to后应用动词原形，如：He is too young to dress himself. (他年纪太小自己不会穿衣服。）
not enough to ／for（不够做⋯⋯）也是个简单句，to 后应该用动词原形，for后应用名词形式，如：He is not old enough to go to school. （他年龄不够上学。）The coat is not big enough for my brother. ( 这外套我弟弟穿不够大。）
so...that( 如此⋯以至于⋯），是个主从复合句。that后应该是完整的一句话，如：He spoke so loud that everyone heard him. (他说话声音那么大以至于大家都听见了。）

Answer 2

它们可以互换
如
He is too young to go to school.
= He isn't old enough to go to school.
= He is so young that he can not go to school.