warn: may range in meaning FROM simple notification of something to be watched for or guarded against TO admonition or threat of violence or reprisal: the weather bureau ~ the coastal areas to prepare for a hurricane.


forewarn: stresses timeliness and regularly imply a warning in advance of a foreseen risk or danger: they had been ~ of the danger, and were prepared when it arose.


caution: suggests giving advice that puts one on guard or suggests precautions against EITHER a prospective or present risk or peril: the doctor ~ him against overeating.


warn: 使用泛围广,从简单提醒注意到警告或威胁报复，forewarn提前警告: 强调及时，提前警告预测到的风险，caution: 提建议,预防已知或未知风险, 所以比warn范围窄。



记忆方法:  1）WFC勿犯错，警告自己。


          2）警告的意思是告知可能的危险或风险mean to let one know of approaching or possible danger or risk.