英语中怎样表示警告

1.用动词warn的现在时、现在进行时、have to warn形式: I warn you not to go skating on such thin ice.我警告你不要在这样薄的冰上溜冰。 I′m warning you that if you lie to me,I′ll beat you.我警告你,如果你对我撒谎,我就揍你。 I have to warn you that some danger hangs over you.我得警告你有危险。 2.用含有look out,watch out,mind等动词的祈使句: Look out!There′s a train coming.当心,火车来了。