In a nutshell, the imparfait is used for incomplete actions while the passé composé is reserved for completed ones, but of course it's more complicated than that.

Can you have passe compose and imparfait in the same sentence?

Use of passé composé and imperfect

Unlike the imperfect, which is used to describe settings or habitual actions in the past, the passé composé is the tense of choice for describing events, actions which advance the narrative. Frequently the two tenses will be used in the same passage, even in the same sentence.

What is another name for passe compose?

In British teaching of French, the passé composé is usually known as the perfect tense. The passé composé is formed using an auxiliary verb and the past participle of a verb.