Be very careful with this stuff, it can be dangerous if it isn't handled properly.

这东西一定要小心,稍不注意的话就会有危险。

Careful on those stairs!. [+ on]

走那几段楼梯要当心!

We had to be very careful not to be seen.

我们得小心翼翼,不能被发现。

Pupils will need careful guidance on their choice of options.

小学生在作出选择时需要悉心指导。

He has decided to prosecute her after careful consideration of all the relevant facts.

在认真考虑了所有相关事实后,他决定起诉她。

What we now know about the disease was learned by careful study of diseased organs.

我们目前对该疾病的认识是通过对病变器官的仔细研究得来的。

I think you should be careful about talking of the rebels as heroes. [+ about/of]

我觉得你说话应该小心,不能把反叛分子当英雄。

It is important, I think, for everyone to be careful about claiming victory.

我想,每个人宣布胜利时都应该慎重。

You will have to make a special effort to train your child to be careful with her pocket-money.

你得格外注意培养孩子的节俭意识，零花钱要省着花。

It would force industries to be more careful with natural resources. [+ with]

这将迫使企业更加节约资源。

You can't be too careful when a young child is near water.

孩子在水边时,还是越小心越好。