Negative sentences in Chinese
A negative sentence (否定句) is constructed by adding a negative particle before the predicate.
The negative sentences in the present and future tenses
To construct a negative sentence in the present and future tense, we need to use the particle 不 
before the predicate.
before the predicate.Scheme
subject
不
predicate
Examples
我不喜欢游泳
I don't like swimming
wǒ bù xǐhuan yóuyǒng
他不是医生
He's not a doctor
tā bú shì yīshēng
Pay attention
When the particle 不 comes before words with the 4th tone, it is pronounced with the 2nd tone — bú.
The verb 有 and phrases beginning with 有 are always preceded by the negative particle 没 .
and phrases beginning with 有 are always preceded by the negative particle 没 .Examples
他没有笔
He has no pen
tā méi yǒu bǐ
这没有意思
It's not interesting
zhè méi yǒuyìsi
The negative sentence in the past tense
To form a negative statement in the past tense we use the negative particle 没 or 没有 .
or 没有 .
Pay attention
The phrase 没有 here is a negative adverb and cannot be translated as “not to have”.
Scheme
subject
没(有)
predicate
Examples
他没出差
He didn't go on a business trip
tā méi chūchāi
我们没有见面
We didn’t meet
wǒmen méiyǒu jiànmiàn
You cannot use 没 and 没有 in the past tense with these words:
1) with verbs that don't indicate an action. For example：
在
是
知道
是
知道
Pay attention
These verbs can only be preceded by 不.
Examples
我昨晚给你打电话，但是你不在家
I called you last night, but you weren't home
wǒ zuó wǎn gěi nǐ dǎ diànhuà, dànshì nǐ bú zài jiā
2) with verbs that denote emotions and feelings. For example：
爱
恨
怕
恨
怕 Examples
我从来不爱你
I never loved you
wǒ cónglái bú ài nǐ
3) with modal verbs. For example:
可以
要
应该
要
应该 Examples
他不能来
He couldn't come
tā bù néng lái