来自PIE*wer,覆盖，保护，看管，看护，词源同ward,ware。引申词义提醒，警告。词义演变比较monster,admonish.

1. He spends his spare time visiting schools to warn pupils off drugs.

他用自己的业余时间访问学校，告诫小学生远离毒品。

2. Signs across the entrances warn all visitors to stub out their cigarettes.

入口处的告示牌提醒游客们熄灭香烟。

3. Lawrence kept on butting me but the referee did not warn him.

劳伦斯不停地用头撞我，但是裁判并没有警告他。

4. I must warn you against raising your hopes.

我必须警告你不要期望过高。

5. Analysts warn us away from drawing any conclusions.

分析家劝告我们不要妄下结论。