L’imparfait – the imperfect tense
The”imparfait” describes ongoing actions and states of being in the past tense, as well as describing habitual actions in the past tense.
About.com gives a nice explanation of the imperfect, with a conjugation table, and quiz as well.
1) Habitual actions – “used to”
2) Physical and emotional descriptions
3) Actions or states of an unspecified duration
4) Background information combined with passe compose- when one action interrupts another already going on
5) Wishes or suggestions
6) Conditions in “si” clauses – similar to “what if” in English
7) With the expression “être en train de” and “venir de” in the past tense
It is formed by using the present tense for the “nous” form, and dropping the -ons to get the stem. Then add the appropriate endings:
Practice with etre in the imperfect.