I understand that l'imparfait occurred habitually in the past, and passé composé happened only once.

However I'm not sure how to form this sentence:
Some thought his work was grotesque, others thought it was interesting.

Certains critiques ont pensé que son travail a été grotesque, mais autres ont pensé qu'il a été interessant.

OR

Certains critiques pensaient que son travail était grotesque, mais autres pensaient qu'il était interessant.

Is this even a valid question? Haha!
Merci!

intéressant

Of course it is a valid question! Often the speaker is the only one who can decide which to use - l'imparfait or le passé composé.

With the passé composé, it would imply either the first time they thought that or the last time they thought that or for a specific period of time (with time limits.)

With the imparfait, it implies that they were holding that thought.

Let's also look at the English translation. With the passé composé the English would be: they DID think that/they thought that

With the imparfait: they WERE thinkING that/they USED TO think that/they thought that.

Having both tenses in the past and distinguishing between them makes the French language so rich !

Sra (aka Mme)

Ah! Light bulb! Merci beaucoup!

And as for the 2 tenses in the past, I find conjugating fun, but not having to think about HOW to use them :)

Here is a picture you might have in mind.

For the passé composé someone is taking a snapshot or a series of snapshots = / / / / /

For the imperfect someone has the movie camera grinding away = ~~~~~~~~~~~~~~~~

Sra (aka Mme)

Yes, it is a valid question! I'm glad you're seeking clarity.

In this case, you are correct that the imparfait tense is used to express habitual actions or ongoing states in the past, while the passé composé tense is used to express a one-time action or an action that happened in the past and is complete.

To form the sentence "Some thought his work was grotesque, others thought it was interesting," you can use the imparfait tense to express the ongoing states of thinking and the passé composé tense to express the completed action of thinking.

Here are the two possible ways to form the sentence correctly:

1. Certains critiques pensaient que son travail était grotesque, mais d'autres pensaient qu'il était intéressant.
- In this sentence, both "pensaient" (thought) and "était" (was) are in the imparfait tense because the thinking was ongoing or habitual.

2. Certains critiques ont pensé que son travail était grotesque, mais d'autres ont pensé qu'il était intéressant.
- In this sentence, both "ont pensé" (thought) and "a été" (was) are in the passé composé tense because the thinking is seen as a completed action.

Both versions are grammatically correct, but the choice between the imparfait and passé composé depends on the intended meaning you want to convey. If you want to emphasize ongoing or habitual thinking, you can use the imparfait. If you want to emphasize completed actions, you can use the passé composé.

I hope this explanation helps! Don't hesitate to ask if you have any further questions.