但too...to在下列情况下却表示肯定含义:
⑴当too前或to前有否定词构成双重否定时.
eg:English is not too difficult to learn.
英语并不太难学.
He is too wise not to see that.
他很聪明,不会不懂这一点.

⑵当too后是glad,pleased,happy,delighted,satisfied,ready,willing,kind,apt,good,true,easy,near,careful,well,
early,delicious,eager,anxious等形容词或副词时.
eg:They are too anxious to leave.
他们急于离开.
He is too ready to help others.
他总是乐于助人.
与这些词连用时,too前还常加上only,all,but,just,simply等副词,意思不变,因为这些词加上too后与very同义.
eg:I"m only too glad to see you .
见到你非常高兴.
They are but too pleased to hear the news.
他们听到这个消息,非常高兴.

⑶与cannot连用时.
eg:You cannot be too careful(=You can never be careful enough) to do your homework.
你做作业越仔细越好(=无论怎样仔细也不过分).

⑷当不定式在句中作定语或真正的主语时.
eg:There are too many problems to be solved.
有很多问题有待解决.
It is too much to say that he is a fool.