be careful with / of the man中用介詞with和of意思不一樣：用　　

be careful with 表示“對……小心（謹(jǐn)慎）”　　

be careful of表示“當(dāng)心或提防”。　　

be careful in doing 這里的in doing 可以視為時間狀語，意思是“在做某事時”。　　

be careful to do中的不定式是目的狀語。如：　　

He is careful in crossing the road. 過馬路時要小心。　　

He is careful to avoid mistakes. 他很小心，以防出錯。