Imperfetto introduction

- Imperfetto. The imperfetto expresses the idea of an action in the past that was ongoing.
(You can find an introduction to the imperfetto in Italian: the Easy Way on page 237. Practice Set 95.)

The imperfetto can be translated into English with:
Suonavo il piano.
I used to play the piano.
I would play the piano... (meaning: "I used to play the piano.")
I was playing the piano... (when suddenly something else happened)*
I was playing the piano. (ongoing in the past, with no mention of starting or stopping)
*Nowadays, some Italians use the imperfetto of "stare plus the gerund" for this construction, rather than the imperfetto: "Stavo suonando il piano..."

Here's a comparison with the other past tense we have studied, the passato prossimo.
L'imperfetto: Leggevo un buon libro. - I was reading a good book.
Il passato prossimo: Ho letto un buon libro. - I read a good book. (or) I have read a good book.
L'imperfetto: Cantavamo ogni sera. - We used to sing every evening.
Il passato prossimo: Abbiamo cantato ieri sera. - We sang last night.

L'imperfetto is a one-word conjugation, formed by taking the stem of the verb and adding these endings:

-vo_____-viamo
-vi______-vate
-va_____-vano

If you want to practice saying the imperfetto out loud, make sure you put the stress on the right syllable.
Most grammar books have it marked. Here (parlare) is an example of the location of the stress:

parlare (l'imperfetto):
parlavo____parlavamo
parlavi____parlavate
parlava____parlavano
_
leggere:
leggevo_____leggevamo
leggevi_____leggevate
leggeva_____leggevano
_
dormire:
dormivo_____dormivamo
dormivi_____dormivate
dormiva_____dormivano

Some irregular verbs:
essere:
ero_____eravamo
eri_____eravate
era_____erano
fare:
facevo_____facevamo
facevi_____facevate
faceva_____facevano