Learn Portuguese (Portugal): Vocês não podem fumar no hospital.

When we use the modal verb poder (can/may) with another action, only poder gets conjugated. Here, it becomes podem to match Vocês. The second verb, fumar (to smoke), stays in its original dictionary form (the infinitive). Think of it like English: we say 'you can smoke', not 'you can smokes'.

Wait, doesn't podem usually mean 'they can'? Why is it used for 'you' here?

In European Portuguese, Vocês (plural 'you') always takes the third-person plural verb conjugation. This is the exact same form used for eles and elas (they). So, eles podem means 'they can', and vocês podem means 'you (all) can'.

Where does the negative word não go when we have a modal verb plus an infinitive?

In Portuguese, não is placed directly in front of the conjugated verb. Here, it goes right before podem. You will almost never put it between the two verbs, because podem não fumar would change the meaning entirely to 'you can choose not to smoke'.

Why do we say no hospital instead of em hospital?