不能 最多也只可以是warn sb not to do 如果想用never,就加在从句里
warn 动词
1.to tell someone of a possible future problem or danger so they can try no prevent it or avoid it告诫,提醒
用法：to warn of sth,to warn sb of sth,to warn that...,to warn sb that...
例子：1.The morning paper warned of serious delays at the airport.晨报提醒大家注意机场误点情况严重.
2.He warned his students that they would have to work very hard to pass.他告诫学生必须非常努力才能通过考试.
3.I warn you it's going to be very cold.我提醒你天气会变得很冷的.
4.His boss had warned her about difficult customers.
他的老板已提醒过她有些顾客很难应付.
2.to advise sb not to do something because of a possible problem or danger in the future 警告（某人不要做某事）
例子：I warned her not to go near the dog,but she ignored me.
我警告过她不要走近那条狗,但她不听我的话.