Be careful when crossing the road.
过马路时应该小心
You can't be too careful! 无论怎样小心也不会过分!
You should be careful of the traffic.你应该小心交通事故
The more careful you are , the better result you w搜趣网ill get.你做事越小心，对你以后的结果越好
Be careful about the precision of detail in your descriptions. 在你的描述中，必须认真地考虑细节的精确度。
望采纳

例句:
Be careful of the dog; it sometimes bites people.
留心那条狗，有时候咬人。
Be careful of that horse it often kicks.
小心那匹马--它常尥蹶子。
Be careful of that viper; he is dangerous.
小心那个阴险的人，他很危险。

John was careful not to say anything about this to her.
约翰小心翼翼,避免向她提及此事。

be
hVdiAy60;careful是一般的警告或劝告用语，可用于各种情况。如：
                   Look out！You’ll hit that car．当心！你要撞上那辆汽车了。
                    Look out for the rock in the river. （后接for短语）小心河里的石头。
                   It’s the first time for you to travel alone．You must  take care．          这是你第一次独自旅行，一定要小心。
be careful可单独使用，也可跟动词不定式或of／with短语。如：
                           Be careful not to lose the key．当心不要丢了钥匙。
                     www.souquanme.com      You’ d better be careful with your handwriting.
          搜趣网0;             你最好书写认真些。
       //www.souquanme.com;                    Be careful of your health．爱护你的身体。