had的否定形式是直接在had后面加not，即had not。had可作助动词和动词，作为助动词时，有时代替if用于从句句首，表示某种情况可能发生但并未发生；作为动词时，是have的过去分词和过去式形式，意为持有、由……组成、带有。
一、had的意思及用法介绍
1、作为助动词时，有时代替 if 用于从句句首，表示某种情况可能发生但并未发生。
例句：Had he succeeded, he would have acquired a monopoly...
要是他当时成功了，他就会取得垄断地位。
2、作为动词时，意为有;持有;占有;由…组成;显示出，带有(性质、特征)。
例句：We've had one or two problems ─ nothing serious.
我们有一些问题，不过没什么大不了的。
I had some idea of what the job would be like.
我对于这份工作有了一些了解。
He had to go to the hospital for treatment.
他不得不去医院接受治疗。
I've had to put my plans into cold storage.
我不得不把我的计划暂时搁置起来。
二、had not的意思及双语例句
had not意为没有。
例句：The work had not been done very thoroughly.
这工作做得不太认真。
Her looks had not survived the ravages of time.
她的容颜未能幸免于时间的摧残。
The treaty was declared invalid because it had not been ratified.
条约没有得到批准，因此被宣布无效。
Tessa was evasive about why she had not been at home that night.
特萨对她那天晚上不在家的原因避而不谈。
It niggled him that she had not phoned back.
她没给他回电话，这使他有些不安。
