be careful的各種搭配：
1.be careful后跟about
be careful about sth講究，小心，當心；慎重的，注意...的；對...小心
be careful about doing sth 慎重、小心、當心做某事
2.be careful后跟of
be careful of sth愛護、關切、掛念、呵護；當心、留意、注意
be careful of the traffic. 注意交通安全。
be careful of/as to wh-從句（of在后接wh-從句時常省略）
3.be careful后跟with
be careful with 小心處理；對…謹慎 ；節儉的、節省的
be careful with the/your money花錢精打細算；吝嗇、小氣
be careful with小心火
4.be careful for關心、惦記
5.be careful in...在...方面、過程中小心、注意