你的问题属于双重否定句!
1．否定词 no／not等＋表示否定意义的形容词.例如：
He has no small reputation as a scientist．他是名气很大的科学家.
No way is impossible to courage．勇士面前无险路.
Is is not uncommon for students to have friendly relationship with their teach－ers．学生与老师建立友好关系并不罕见.
It is conflict and not unquestioning agreement that keeps freedom alive．使自由保持活力的是冲突而不是绝对的一致.
Nothing is unneccessary．没有什么是不必要的.
2．否定词 no／not／never等＋without…例如：
No smoke without fire·〔proverb〕〔谚〕无火不起烟；无风不起浪.
We cannot succeed without your help．没有你们的帮助,我们就不能成功.
They never meet without quarreling．他们每次见面必吵架.
Nothing to be got without pains but poverty．〔proverb〕〔谚〕只有贫穷是可以不劳而获的.
3．否定词 no／not／never／nobody／few等＋具有否定意义的动词或短语.例如：
There is no denying the truth．真理是不能否认的.
The tart reply did not discomfort him．那尖刻的回答并没有使他难过.
The Dole company says it is the biggest fruit packing company．Nobody dis－agrees．多尔公司说它是世界上最大的水果罐头公司.没有人对此提出异议.
In spite of the increased debts,few fail to repay．尽管借债越来越多,但很少有人不能偿还欠款.
英语双重否定句不仅限于以上三种句型,还有其他一些形式.如：
It is impossible not to do the work．不做这件工作是不可能的.（否定形容词在前,而否定词在后,否定不定式）
I'd review all the facts of the case and,not infrequently,wonder if I hadn'tmade a poor decision．我会重温那位急诊病人的整个病情,常常怀疑自己做出了不妥的决定.（否定词后接具有否定意义的副词）
But it seemed no impossibility to Marconi,…但在马可尼看来,这不是不可能的,……（否定词后接具有否定意义的名词）
There is no rule that has no exception．任何规则都有例外.（两个相同的否定词重复使用）
