Learn French: Tu ne dois jamais mélanger la pâte sans la levure. - You must never mix the dough without the baking powder.

In French, negative pairs like ne ... jamais (never) or ne ... pas (not) wrap directly around the conjugated verb. Since dois is the conjugated verb here, it becomes tu ne dois jamais. The second verb, mélanger, stays outside this negative "sandwich."

Why is mélanger in the infinitive form rather than conjugated to match tu?

When two verbs appear together and the first one is conjugated (like the modal verb dois), the second verb stays in the infinitive (unconjugated) form. The conjugation of the first verb is enough to show who is doing the action.

We are learning about conjunctions that take the subjunctive. Why isn't the subjunctive used here with sans?

You only need the subjunctive when you use a conjunction that introduces a new clause with a verb, like sans que (without [someone doing something]) or avant que (before [something happens]). In this sentence, sans is used as a simple preposition followed directly by a noun (la levure). Since there's no verb after it, the subjunctive doesn't apply!

The translation says "baking powder", but isn't levure the word for yeast?