The Italian prepositions per, su, con, and fra/tra stand for many different words and are used in a variety of grammatical constructions. The preposition per ("for" in English) is used to indicate the following:

　　1. Movement through space:

　　Sono passati per Roma. (They passed through Rome.)

　　Sono passati per Londra. (They passed through London.)

　　2. Duration of time:

　　Ho lavorato per un anno intero. (I worked for an entire year.)

　　Ho lavorato per due giorni senza una pausa. (I worked for two days without a break.)

　　3. Destination:

　　Questa lettera è per il direttore. (This letter is for the director.)

　　Another useful preposition to know is su (on). Su is used in Italian to indicate location or a topic of discourse. For example:

　　Il libro è sul tavolo. (The book is on the table.)

　　Il cuscino è sul divano. (The cushion is on the couch.)

　　È una conferenze sull'inquinamento industriale. (It is a conference on industrial pollution.)

　　The use of preposition con is similar to your use of the English "with":

　　È uscito con la cugina. (He left with his cousin.)

　　Sono andato con la mia famiglia. (I left with my family.)

　　Taglia il pane con quel coltello. (He/she cuts the bread with that knife.)

　　Apre la porta con questa chiave. (He/she opens the door with this key.)

　　Ha risposto con gentilezza. (He/she responded with gentleness.)

　　Lei ha gridato con gioa. (She screamed with joy.)

　　Finally, there is the preposition tra or fra (these words are fraternal twins and interchangeable in all cases), which may be used in the sense of "between" (whether between two locations, things, or people), or to indicate a time in the future with respect to the speaker. For example:

　　Livorno è fra Roma e Genova. (Livorno is between Rome and Genova.)

　　Silvano è fra Maria e Davide. (Silvano is between Maria and Davide.)

　　Fra qualche giorno arriverà la primavera. (In a few days spring will arrive.)

　　Tra alcuni ore arriveremo. (In a few hours we'll arrive.)