兩者區別：be careful with表示做某事時很小心、仔細或對某人某物很關心。with後接名詞或動名詞，be careful of意思是當心；留意；注意，後接名詞、動名詞或從句，形容人很細心。
be careful with造句：
You are careful with my cat。你對我的貓很關心。
We've got to be careful with everything we do。我們做任何事都要仔細。
Be careful with that 's got a keen edge。小心那把刀子，他有鋭利的鋒刃。
be careful of造句：
Be careful of the dog，it sometimes bites people。當心那條狗，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。
