Cách sử dụng
To warn someone means to let them know that something bad might happen, so they can be careful or take steps to avoid it. For example, if you see a sign that says "WARNING: Slippery Surface," it means you should be careful so you don't fall. You might also warn your friend not to eat the last piece of cake because it's for someone else. So when you use the word "warn," you are telling someone that there is a potential danger or problem that they should be aware of.