Thank you very much. It helps me very much . Grazie mille.

In Italian different verbs call for different preposition when you build a sentence with the infinitive. English always use "to" with the verbs in the infinitive form. But also English can use different prepositions when using the -ing form (for instance "I think to quit" and "I think of quitting") Other Italian verbs and their prepositions when connecting to another verb. Penso di fare = I think to do prova a prendere = try to take andiamo a giocare = let's go to play Cercate di esserci = try to be there And many verbs don't use any preposition Voglio crederti = I want to believe you These are the so-called "verbi servili" ("servants verbs): volere, potere, dovere and sapere (this last only when meaning of "being able to"). In English just "must" and "can" act this way I believe. For the others, I suggest you to look on a dictionary to know if the verb calls for "a" or "di"