兩者區(qū)別：be careful with表示做某事時很小心、仔細(xì)或?qū)δ橙四澄锖荜P(guān)心。with后接名詞或動名詞，be careful of意思是當(dāng)心；留意；注意，后接名詞、動名詞或從句，形容人很細(xì)心。

be careful with造句：

You are careful with my cat。你對我的貓很關(guān)心。

We've got to be careful with everything we do。我們做任何事都要仔細(xì)。

Be careful with that knife.It's got a keen edge。小心那把刀子，他有銳利的鋒刃。

be careful of造句：

Be careful of the dog，it sometimes bites people。當(dāng)心那條狗，它有時候會咬人。

Be careful of that sinister man，He is dangerous。留意那個陰險的人，他很危險。

You must be careful of your health。你一定要注意你的健康。