29.cannot ...too...
We cannot praise him too much.我们无论怎样称赞他都不过分。
I cannot thank you enough.我对你感激不尽。
30.It be＋时间段＋before...，It is ＋时间段＋since...
It be＋时间段＋before... 该句式中的时态为将来时和过去时，意思是“过多久才……”。
It will be five years before we meet again.再过5年我们才能再相见。
It was not long before the enemy was driven out of their motherland.不久敌人被赶出了他们的祖国。
It is ＋时间段＋since...，该句式的时态为一般现在时和现在完成时，从句多用一般过去时，表示“自……到现在有多长时间”。
It is ten years since she left me.自从她离开我已经有10年了。
须注意：当从句的谓语是瞬间谓语动词时，照字面意义理解；当从句谓语动词是延续性谓语动词时，理解为
字面意义的反义。
It is ten years since he stayed here.他离开这儿有十年了。
It is a long time since he studied English.他好久没有学习英语了。
31.too...to 该句式表示“太……以致不能……”这一句式具有否定意义。
He is too excited to say a word.他激动得一句话也说不出来。
The child is too young to go to town by himself.孩子太小，不能一个人进城。
但在下列几种形式中不表否定意义：
⑴too ready/anxious/eager/easy/willing to do...
He is too ready to help others.他非常乐于助人。
They were too anxious to leave.他们急着要离开。
⑵only/but/all too＋形容词＋to do sth.
I am only too glad to go with you.我极愿意跟你去。
We are but too willing to do it for you.我们很乐意为你服务。
⑶not/never too...to ...
He is not too young to marry.他不算太年轻，可以结婚了。
It is never too late to mend.亡羊补牢，未为迟也。
⑷too...not to...
He is too angry not to say that.他在盛怒之下，难免会说出这种话来。
He was too experienced not to know it.他经验丰富， 这一点他不会不知道的。
cannot 和 too,enough 等连用，表示“无论怎样也不为过”，“越……越……”。
You cannot be too careful.你越仔细越好。
We cannot praise him too much.我们无论怎样称赞他都不过分。
I cannot thank you enough.我对你感激不尽。
30.It be＋时间段＋before...，It is ＋时间段＋since...
It be＋时间段＋before... 该句式中的时态为将来时和过去时，意思是“过多久才……”。
It will be five years before we meet again.再过5年我们才能再相见。
It was not long before the enemy was driven out of their motherland.不久敌人被赶出了他们的祖国。
It is ＋时间段＋since...，该句式的时态为一般现在时和现在完成时，从句多用一般过去时，表示“自……到现在有多长时间”。
It is ten years since she left me.自从她离开我已经有10年了。
须注意：当从句的谓语是瞬间谓语动词时，照字面意义理解；当从句谓语动词是延续性谓语动词时，理解为
字面意义的反义。
It is ten years since he stayed here.他离开这儿有十年了。
It is a long time since he studied English.他好久没有学习英语了。
31.too...to 该句式表示“太……以致不能……”这一句式具有否定意义。
He is too excited to say a word.他激动得一句话也说不出来。
The child is too young to go to town by himself.孩子太小，不能一个人进城。
但在下列几种形式中不表否定意义：
⑴too ready/anxious/eager/easy/willing to do...
He is too ready to help others.他非常乐于助人。
They were too anxious to leave.他们急着要离开。
⑵only/but/all too＋形容词＋to do sth.
I am only too glad to go with you.我极愿意跟你去。
We are but too willing to do it for you.我们很乐意为你服务。
⑶not/never too...to ...
He is not too young to marry.他不算太年轻，可以结婚了。
It is never too late to mend.亡羊补牢，未为迟也。
⑷too...not to...
He is too angry not to say that.他在盛怒之下，难免会说出这种话来。
He was too experienced not to know it.他经验丰富， 这一点他不会不知道的。
