"Passé composé" vs imparfait" [duplicate]

Question

Is there any efficient way to differentiate between "passé composé" and "imparfait"? In the current state of my knowledge , I am able to differentiate only for certain cases , e.g I know descriptions of weather use "imparfait" , habitual actions use "imparfait", long timing uses "imparfait" etc., but for some questions, I am still not able to know which tenses to use; for example,

1) Nous jouions aux échecs depuis un bon moment. why do we use "jouions" instead of "avons joué" ?

2) J.K Rowling a écrit Harry Potter. Why is it we use "a écrit" instead of écrivait ? Isn't this continuous and don't we know the exact "moment" when she wrote the text ?

I need some suggestions of study links or anything that will help me in understanding when to use "passé composé" or "imparfait".

Answer 1

The main thing that could help you is that for passé composé the action happened and is finished.

Passé composé is used to answer the question "What happened ?"

Imparfait is used to answer the question "What happened during the action ?"

For your exemples :

J.K Rowling a écrit Harry Potter

She finished to write Harry Potter, the action ended --> passé composé

Isn't this continuous and don't we know the exact "moment" when she wrote the text ?

You would use "écrivait" if you indicate "where", "when" or "why" at the end of the sentence.

Exemple : J.K Rowling écrivait Harry Potter durant les nuits d'été.

Nous jouions aux échecs depuis un bon moment

They're still playing --> imparfait

Maybe this links could help you more :

https://www.francaisfacile.com/exercices/exercice-francais-2/exercice-francais-17862.php https://francais.lingolia.com/fr/grammaire/les-temps/imparfaitpasse-compose