否定：全部否定和部分否定
eg.All the birds can not fly.
Not all the birds can fly.不是所有的鳥都會飛。
1.部分否定
eg.All the birds can not fly.並非所有的鳥都會飛。
None of the birds can fly.所有的鳥都不會飛。
代詞或副詞如all，both，every，everybody，every day，everyone，everything，everywhere等與not搭配使用時，表示部分否定，意思為「並非都是"等。
eg.All is not gold that glitters.發光的並非都是金子。= Not all is gold that glitters.
2.全部否定
英語中常用not，none，nobody，nothing，nowhere，neither，never等表示全部否定的概念。
eg.Nothing in the world is difficult for one who sets his mind to it. 世上無難事，只怕有心人。
eg.W:Daddy,I've decided to give up science and go to business school.
M:Well,it is your choice as long as pay your own way,but I should warn you that not everyone with a business degree will make a successful manager.
Q:What do we learn from the conversation?
A.The man doesn't have money for his daughter's graduate studies.
B.The man doesn't think his daughter will get a business degree.
C.The man insists that his daughter should pursue her studies in science.
D.The man advises his daughter to think carefully before making her decision.
雙重否定
1.在閱讀當中出現的頻率更高一些。在一個句子中出現兩個否定詞：not，never，hardly，scarcely，rarely，seldom，few，little，none等，雙重否定表示肯定的概念。
eg.No one can command others who cannot command himself.
A perpson can command others who command himself. 正人先正己。
eg.Without the ability to think critically,to defend their ideas and understand the ideas of others, they can not fully participate in our democracy.
如果沒有能力進行批判性思維，維護自己的觀點，並理解他人的觀點，他們就不能充分的參與我們的民主政治中來。
2.形式否定，意義肯定
eg.A man can never have too many ties. 一個男人可以擁有很多的領帶。
A woman can never have too many dresses. 一個女人擁有再多的衣服也不為過。
eg.We can hardly praise his achievement too much. 對他的成就我們無論怎樣讚揚也不過分。
eg.A mother can never be patient enough with her child. 一個母親對她的孩子再怎麼耐心也不為過。
A teacher can never be strict enough with his students. 一個老師對他的學生再怎麼嚴格也不為過。
這種形式主要運用於閱讀當中。