Could you explain to me which of the sentences below is correct and why?
You should ban cars from city centers.
You should ban cars in city centers.
I suppose that the first sentence is a proper one, but I can’t understand why there is a preposition from.
This is an example from an online dictionary freesearch.co.uk, take a look at this:
She was banned from driving for two years.
This case is a coherent one for me.
Maybe there are other similar examples like this above, you mean, a verb + from if you want to express prohibition.
These are two quite separate verbs in terms of meaning. Prevent means stop something happening. There is a saying Prevention is better than cure referring to illness and disease. This means it’s better to stop an illness occurring rather than try and find a cure for it. Prevent is used with the preposition from as in: They were prevented from entering the building by the police - in other words the police didn’t let them go in. Exile means remove someone to another country from their own country. More often this is used as a noun with the expression: live in exile, which can be because you are forced to leave your own country or alternatively because you choose to live in another country.