In Italian, to express an action that began in the past and is still going on in the present, use the verb in the present tense + da + length of time. This construction does not exist in English, where you would use the present perfect tense. Here are a few examples:

　　Leggo questo libro da una settimana.(I've been reading this book for a week.)

　　Prendiamo lezioni di italiano da molti mesi.(We've been taking Italian lessons for many months.)

　　To ask how long something has been going on, use da quanto tempo + present-tense verb:

　　Da quanto tempo leggi questa rivista?(How long have you been reading this magazine?)