Ce sur quoi in French: what you work on, agree on or base an idea on

Build ce sur quoi from travailler sur, se mettre d’accord sur and reposer sur. Compare named relatives and check agreement in a short project scene.

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In short

Ce sur quoi means “what … on” when the French expression uses sur: Nous travaillons sur cela → Voici ce sur quoi nous travaillons. It leaves the thing unnamed. With a named noun, use an agreeing relative: le projet sur lequel nous travaillons.

Yellow the idea to rememberBlue French to learn

Three neighbours sit around a small table preparing an interview, with a simple unbranded audio recorder between them.
Interview planning gives ce sur quoi nous travaillons a setting. Illustration: Atelier

Follow a project discussion

Préparer une rencontre sur les langues
  1. Nora

    Vous préparez une rencontre ? Montrez-moi ce sur quoi vous travaillez.

    Are you preparing an event? Show me what you are working on.

  2. Léo

    Nous préparons trois entretiens avec des familles du quartier.

    We are preparing three interviews with families from the neighbourhood.

  3. Nora

    Et vous avez choisi les questions ?

    And have you chosen the questions?

  4. Léo

    Oui. Ce sur quoi nous sommes d’accord, c’est la durée : vingt minutes par entretien.

    Yes. What we agree on is the length: twenty minutes per interview.

  5. Nora

    Voilà une bonne base. Expliquez aussi ce sur quoi repose votre choix.

    That is a good starting point. Also explain what your choice is based on.

Named noun or unnamed thing?

le projet sur lequelthe project that … on

Focus: A named masculine singular noun

Le projet sur lequel nous travaillons avance bien.
The project we are working on is progressing well.

la question sur laquellethe question that … on

Focus: A named feminine singular noun

La question sur laquelle nous travaillons concerne les langues familiales.
The question we are working on concerns family languages.

ce sur quoiwhat … on

Focus: An unnamed thing; no gender change

Ce sur quoi nous travaillons concerne les langues familiales.
What we are working on concerns family languages.

How do you find the subject after ce sur quoi?

Ce sur quoi reposent tes conclusions doit être expliqué.

What your conclusions are based on must be explained.

Inside the relative, plural tes conclusions controls reposent. The whole phrase ce sur quoi… is the subject of singular doit.

Compare the simple statement: Tes conclusions reposent sur ces observations. Put the complement first and tes conclusions still controls the verb. This gives ce sur quoi reposent tes conclusions.

Question 1No account needed
Keep the construction travailler sur.Voici ___ nous travaillons.

Choose one answer.

Answer and explanation

ce sur quoi. The original construction contains sur, which stays before quoi in the neutral relative.

Question 2No account needed
Complete the named feminine relative.La question ___ nous travaillons est précise.

Choose one answer.

Answer and explanation

sur laquelle. Laquelle agrees with the named feminine singular noun question.

Question 3No account needed
Choose the verb agreeing with the subject inside the relative.Explique ce sur quoi ___ tes conclusions.

Choose one answer.

Answer and explanation

reposent. The subject is plural tes conclusions, so the verb is reposent.