I'll talk to him, but it will do no good.

我会和他说的，但不会有用。

However, if you are always sitting on the sofa and do no exercise at all, you will put on weight and harm your health.

然而，如果你总是坐在沙发上，完全不锻炼，你会增加体重并损害健康。

She worships the ground he walks on, thinking he can do no wrong.

她崇拜他，认为他不会犯错。

She worshiped the ground he walked on, believing he could do no wrong.

她崇拜他走过的每一寸土地，相信他不会犯错。

No matter what we do(no matter what we do).

无论我们做什么。

At least do no harms

或者说，至少不作恶

You do no need a crystal pellet.

你不需要水晶球。

A man can do no more than he can.

凡事都应量力而行。

A man can do no lot dawn he can.

一个人能做的不会比他能的多。

Do no use it under wet environment.

使用一枚五号干电池.