Many times double negative is used in Chinese sentences to make an affirmative effect.
Double Negative 双重否定
The affirmative effect in a double negative sentence is much stronger than in a single affirmative sentence. A double negative is adopted to strengthen or emphasize the affirmative tone.
There are three forms for double negation:
1. Two negative adverbs used in a sentence.
2. One negative adverb and one negative verb used in a sentence.
3. A negative adverb or a negative verb in a rhetorical question.