When Slavs use prepositions in English language... :)

Is it... to, at, in, on, of or some other...? :)

Oops, a slip of the tongue... mouth working faster than brain. Let's see, ''...which topics...'' instead of ''...which prepositions...''. Some grammar - ''...have habit...'', missing an article the and ''...those open farmer's market...'', there should be a plural form :), markets.