Old English cearful "mournful, sad," also "full of care or woe; anxious; full of concern" (for someone or something), thus "applying attention, painstaking, circumspect;" from care (n.) + -ful.
权威例句
1. You have to be careful what you say on telly.
在电视上说话时你必须很谨慎。
2. Interior decoration by careful coordination seems to have had its day.
精心搭配的室内装饰似乎已不再受欢迎了。
3. One of the keys to successful business is careful planning.
打造成功企业的关键之一就是要精心策划。
4. This very careful attitude to money can sometimes border on meanness.
这种对待金钱的过分谨慎的态度有时几近于吝啬。
5. The British Government was careful not to act unilaterally.