双重否定是指在同一个句子里同时用两个否定词的情况。
由于这两个否定词都是用于同一事物，它们的否定作用相互抵消，从而表达与否定相反的意思。
英语里常见的否定词有： no, not, none, no one, nothing, nowhere, neither, nobody, never.
当动词前面加上了否定词"not"或它的缩写时，这个动词就被否定。常见的可以放在动词前面的否定词有：cannot, does not, should not, will not, can't, doesn't, shouldn't.
双重否定举例：
错误：I am not going to pay no bills today.
必须去掉一个否定词才能改正这个错误。
正确：I am not going to pay any bills today. ("Any" 不是一个否定词。 .)
正确：I am going to pay no bills today.
另一例：
错误：She cannot make friends with nobody in our school.
去掉其中任何一个否定词就能改正这个错误。
正确：She can make friends with nobody in our school.
正确：She cannot make friends with anybody in our school.
A double negative happens when you put two negative words which refer to the same thing together in the same sentence.
Since the two negative words are talking about the same thing, they cancel each other out and you say the opposite of what you mean.
List of common negatives: no, not, none, no one, nothing, nowhere, neither, nobody, never.
Verbs become negative when a negative word such as "not" or its contraction is added to them: cannot, does not, should not, will not, can't, doesn't, shouldn't.
Example of using a double negative:
Incorrect: I am not going to pay no bills today.
One of the negatives must be removed to correct the sentence.
Correct: I am not going to pay any bills today. ("Any" is not a negative word.)
Correct: I am going to pay no bills today.
Another example:
Incorrect: She cannot make friends with nobody in our school.
To correct the sentence, remove either one of the two negatives.
Correct: She can make friends with nobody in our school.
Correct: She cannot make friends with anybody in our school.