1. can / could not … too 表示“無論怎樣也不過分”。例如：
You cannot be too careful when crossing the street. 穿越馬路時，再怎麼小心也不為過。
You can never be too careful in performing an experiment. 做實驗越仔細越好。
2. can / could not be + enough 意為“無論怎麼都不夠”，表示強烈的肯定。例如：
I cannot thank you enough. 我對你感激不盡。
You can't be careful enough. 你越小心越好。
3. too … not to 表示“太……不會不……”，具有肯定意義。例如：
He is too careful not to have noticed it.
他那麼小心，一定會注意到這一點的。
4. never too … to 是對 too … to 的再否定，表示肯定。例如：
It's never too old to learn. 活到老，學到老。
5. not … for nothing 中， not 用來否定 for nothing ，從而加強了謂語的肯定意義。例如：
He didn't study law for nothing. 他學法律並沒有白費。
Believe me， he did not fly into such a rage for nothing.
請相信我，他勃然大怒是有原因的。
6. nothing if not 表示“極其”，含強烈的肯定意義。例如：
He was nothing if not clever. 他很聰明。
The story was nothing if not interesting. 故事極其有趣。
7. nothing less than 表示“完全是”，有肯定的含義。例如：
What he said was nothing less than a lie. 他說的純屬謊言。
His negligence was nothing less than criminal.
他的粗心大意無異於犯罪。
8. nothing but 表示“只有;只不過”，含肯定意義。例如：
We could see nothing but water. 我們只看見一大片水。
She does nothing but listen to records.
她除了聽唱片什麼也不做。
9. no 的否定意義很強，和具有否定意義的名詞連用，來表示強烈的肯定。例如：
She is no fool. (She is very clever.) 她絕不是傻瓜。
There is no question that Mr. Smith is the boss.
毫無疑問，史密斯先生就是老闆。
10. 雙重否定表示強烈的肯定。例如：
Nobody had nothing to eat. = Everyone has something to eat. 每個人都有吃的。
11. not … until/till 表示“直到……才”，具有肯定的意義。例如：
She didn't stop working until it was 12 o'clock last night.
昨晚 12 點以前，她一直在不停地工作。
12. “否定詞 + so + adj. /adv. + as ”結構從反面表示“最”，是一種強烈的肯定。例如：
It wasn't so bad as last time! 這次不像上次那麼壞!
None is so blind as those who won't see.
沒有比視而不見的人更瞎眼的了。
13. 有些帶否定詞的短語，在使用時並不構成否定意義，即表示肯定意義。例如：
He would go as soon as not. 他非常樂意去。
As often as not the buses are late on foggy days.
遇多霧天氣時，公共汽車經常晚點。
14. 否定的感嘆句、疑問句常表示肯定意義。例如：
Isn't this film interesting? 這電影難道沒趣嗎?
Who doesn't enjoy reading The Dream of the Red Mansion?
誰不喜歡看《紅樓夢》呢?(人人都喜歡看《紅樓夢》。)
15. 以 why don't you do 和 why not do 開頭的疑問句往往表示邀請、建議、指導等，具有肯定意義。例如：
Why don't you introduce her to your parents?
你為什麼不介紹她給你父母認識?
Why not come and see me tomorrow?
明天找我怎麼樣?
