"Di" usually we can translate in english like "of": his role is specify something, a characteristic or possession. With "Da" we can think to "from": means the provenience of a movement, of a time o stuff like this. These are PREPOSIZIONI SEMPLICI, if we add to an article we would have PREPOSIZIONI ARTICOLATE (means prepositions + articles). "Della" is DI+LA, "Dalla" is DA+LA. So you can use them when you need to express a subject of your complement singular and female (article "la"). Examples: "La casa DI Lucia" - "Il tavolo DI legno" "Da questa strada vedo il mare" - "Il negozio è aperto DA martedì A giovedì" "La casa DELLA zia" - "DALLA vacanza in Francia ho portato del formaggio" ________________________________ I hope to be usefull, if you have any question write me a message. Have a nice day! Rolando