This should elicit “you can’t smoke,” or something to that effect. If they say “no smoking,” ask them to elaborate with a full sentence. Start by showing or drawing a picture of a no-smoking sign to your class and asking them what it means.
It uses real-life examples that students see around them every day, so they should have no problem picking up the grammar and putting it into context. This exercise is great for teaching how to use modal verbs for prohibition and obligation.
