The imperfect tense is used to talk about and also describe things that used to happen regularly in the past. Learn how to form sentences using this tense.
There are exceptions, for example être starts differently (so you can't use nous sommes) but the endings are all the same. The stem for être is ét-:
Note that the endings for the imperfect tense are always the same.
Verbs like manger add an extra -e before -a, -o, -u. You take it from nous mangeons and it becomes:
With verbs like commencer, the last -c becomes -ç before -a, -o, -u. Nous commençons - BUT NOT in the nous and vous forms: