becarefulabout/of/withsth或者becarefulabout/in+doingsth皆为:小心,当心,警惕的意思
becarefulwithglasses小心玻璃杯
becarefulofthedog,itsometimesbitespeople留心那条狗,有时候咬人
becarefulabout/ofwhatyousaytohim对他说话可得小心
becarefulabout/incrossingtheroad过马路要留神
heisverycarefulwithhismoney他用钱很仔细