1.I tried to warn him, but he wouldn't listen.
我设法提醒过他，可他就是不听。
2.The computer is programmed to warn users before information is deleted.
这台计算机编程时已设计在信息删除前提醒用户。
3.Traffic signs warn you of other traffic signs ahead.
交通指示牌警告你前面有其他指示牌。
4.I warn him of the danger.
我警告过他说有危险。
5.I did warn you.
我确实警告过你。
6.I did warn him!
我真的警告过他了！
7.Warn everyone of the danger.
警告所有人注意危险。
8.He saw a snake and to warn us of the danger.
他看见一条蛇，并警告我们有危险。
9.We need to warn him.
我们得警告他。