no後面加動詞通常加動詞的ing形式，主要用於一些警示標誌。如：

No smoking 禁止吸菸；No parking 禁止停車；No swimming 禁止游泳；等。

加動詞的ing形式。no後面加動詞ing形式表示不要做某事，如：no parking。

No後面有看似動詞的詞語，其實就是它的名詞用法而已，如：

No use

No doubt

【例句】

It was no use pretending that I had not seen him.

裝作沒看見他是沒有用的。

There was no doubt that he was a fine scholar.

毫無疑問，他是一個好的學者。

規則1：“No+名詞”意思與“not+a/the+名詞”意思相似。沒有“Not+名詞”這一用法。我們不能說：We have not reason to suppose that。

例如：

There is no reason to suppose that…=there is not a reason to suppose that …

規則2： “No+名詞”通常通常可以用“not+動詞+any+名詞”替換。

例如：

We encountered no problems with the calculations= we did not encounter any problems with the calculations.

規則3： be後面的形容詞如果沒有加名詞，則前面加not；如果後面有名詞，則要用no。

例如：

It is not unusual to find strange species in this area.

There are no unusual species in this area.

規則4： 副詞前要使用not：

例如：

Not surprisingly, the cardiovascular system is the first organ system to reach a functional state in an embryo.

規則5：No longer可以寫成較不正式的not…any more/longer。

例如：

This system is no longer used.

This system is not used any more.

This system is not used any longer.

三句話意思一樣。

規則6：“No+形容詞比較級”表示相比較的兩個事物是相同的，例如A is no bigger than B, 表示A並不比B大。

比較下面兩個例句：

X turns out to be no easier than Y. (言外之意： X and Y have the same level of difficulty)

X is not easier to solve than Y. (言外之意：Y is probably easier to solve than X)