提醒你怎么用 warn
及物动词 warn 意为警告；告诫；提醒。其后面的宾语比较复杂，看了下面的小文档，也许会帮你更好地掌握 warn 的用法。
1 . warn 后直接跟名词或代词。如：
They warned her.
warn 后常跟 of/about 短语，即： warn sb. （名词或代数） +of/about ，意思是警告某人有（提防）。 of/about 后接表示（有的）危险的词或短语。如：
She warned me about dangerous road， so I crossed it carefully.
I warned them of danger.
2 . warn 后跟 against 短语， against 后常跟动名词，也可跟名词或代词。 warn sb. against 表示别或提防。如：
I warned you against buying that old car.
3 . warn 后常跟不定式的复合结构，即： warn sb. to do sth. ，意为告诫 / 提醒某人做某事。否定形式为： warn sb. not to do sth. 。如：
The teacher warned her not to be late again.
4 . warn 后也可接 that 引导的宾语从句。如：
I am here to warn you that you have a chance.
The doctors had to warn her that she must be prepared for the worst.
5 . warn 后跟不定式的复合结构与跟 against 短语表达的意思相同。如：
We warned him against standing under the tree when there was a thunderstorm.=We warned him not to stand under the tree when there was a thunderstorm.