be careful of和with的区别：含义不同、用法不同。be careful of中文翻译为“小心”、“注意”，后接名词、动名词或从句；be careful with中文翻译为“照顾”、“对…过细地”，后接做的事情 ，强调干事认真。

be careful of意为小心，注意。是褒义词。

例句：Be careful of the traffic. 

注意交通安全。

Take care of yourself!; Be careful of yourself! 

保重保重。

They had to be careful of floating chunks of ice. 

他们必须当心大块浮冰。

Better be careful of your bookish approach, comrade. 

同志，注意你的书生气！

Be careful of an outburst: they may suddenly bite or scratch you. 

还要小心它们突然爆发，咬你或抓伤你。

Be careful of the yeah-but. The yeah-but will kill your dreams. 

当心“是的，但是…”这句话，它会扼杀你很多梦想。

I think you should be careful about talking of the rebels as heroes 

我觉得你说话应该小心，不能把反叛分子当英雄。

be careful with意为照顾，对…过细地。

例句：Be careful with the glasses. 

小心这些玻璃杯。

Please be careful with my glasses. 

请当心别打碎我的眼镜。

Do be careful with the experiment you're doing. 

在实验中切不可粗心大意。

And be careful with queues at the checkouts. 

在排队结账时要注意。

Also, skin doctors warn people to be careful with sun 

同时，皮肤科专家提醒人们不要过分暴露在日晒环境下。

You might want to be careful with that. You seem a little jittery. 

你可能想对那事小心点，你像是有点神经过敏。