It is a hard and fast contract .

这是一项不能变动的契约。

There are no hard and fast rules.

当然这个是没有任何硬性规定的.

This is not a hard and fast rule.

但这并不是一个牢靠不变的规则.

This distinction isn't hard and fast.

这样的差别并非是一成不变的。

There are no hard and fast rules here.

本文无法提供硬性而快速的规则。

You can't lay down hard and fast rules.

规则不能定得太严太死。

He stuck hard and fast to his principles.

他坚定不移地坚持自己的准则。

There are no hard and fast rules about this.

关于这一点，没有什么硬性的规定。

There is no hard and fast rule about dilution.

至于稀释程度，没有严格的规定。

There are no hard-and-fast rules for success.

通往成功没有什么一成不变的规则。