「不要上当」英文怎么说？

fall for (something)上当

don't fall for (something)不要上当

There are many red packet gambling groups on WeChat and QQ. Gambling never pays. Don't fall for it. 

微信和QQ上有很多红包赌博群，但是赌钱是不会赢的，十赌九输呀！大家不要上当噢！

Many unqualified English teachers are teaching online nowadays and they claim that their lessons are free of charge. Don't ever fall for it. 

现在如今有很多没有资格的英语老师选择在网络上授课，并声称课程免费，你可不要上当呀！