详细内容：o warn people about sharks in the water. ……警告人们当心水里的鲨鱼。
[用法]warn用作动词，意思是“警告”、“警戒”。
[搭配]
1)warn sb.+ that从句
nbsp;nbsp;2)warn sb. of sth.警告某人某事
3)warn sb. to do sth.
告诫某人做某事
4)warn sb. against(doing) sth.
告诫某人当心某事/不要做某事
[举例]
1)I warned him that snakes were dangerous.我警告他，蛇很危险。
2)We are trying to warn children the dangers of smoking.
我们正试图警告孩子们吸烟的危害。
3)Dr Synes warned me to give up my drinking.
Synes大夫劝我戒酒。
4)The notice warned people against swimming in the pool.
公告告诫人们不要在池塘里游泳(联系我时，请说明是在51站台网看到的，谢谢！)
