Paul cherche le moule pendant que je préchauffe le four.

Because the subject is Paul, which is third person singular.
The verb chercher in the present tense goes:

• je cherche
• tu cherches
• il/elle/on cherche
• nous cherchons
• vous cherchez
• ils/elles cherchent

So Paul cherche means Paul is looking for.

French often uses the present tense where English might say either:

• Paul is looking for the mold/tin
• Paul looks for the mold/tin

In a sentence like this, the French present tense usually matches the English present progressive idea: something happening right now.

So Paul cherche and je préchauffe both describe actions in progress.

Pendant que means while. It links two actions happening at the same time.

So:

• Paul cherche le moule
• pendant que
• je préchauffe le four

together mean that Paul is doing one thing while the speaker is doing another.

It is a very common way to connect simultaneous actions in French.

No, not in this sentence.

Que by itself usually means that, which, or is part of other structures.
To mean while, you normally need pendant que.

For example:

• Je lis pendant qu’il cuisine. = I’m reading while he cooks.

If you remove pendant, the meaning changes or the sentence becomes incorrect.

French uses articles much more often than English does. Here, le is the definite article meaning the.

So:

• le moule = the mold / tin / baking pan
• le four = the oven

Even when English might sound natural with a, the, or sometimes no article depending on context, French usually requires one.

It is je préchauffe because the verb begins with the consonant sound pr-, so there is no contraction. French only shortens je to j’ before a vowel sound or a mute h.

So:

• je préchauffe
• but j’aime
• j’habite

Also, préchauffer specifically means to preheat, while chauffer means to heat or to warm up more generally. For an oven, préchauffer le four is the standard phrase for preheating the oven.

It is true that many French nouns ending in -e are feminine, but this is only a tendency, not a rule.

Moule can actually be:

• masculine: un moule = a mold, baking tin, pan, cast
• feminine: une moule = a mussel

So in this sentence, le moule is masculine because it means the kitchen object, not the shellfish.

Usually, yes. Chercher most often means to look for or to search for something.

Examples:

• Je cherche mes clés. = I’m looking for my keys.
• Elle cherche un travail. = She’s looking for a job.

A useful point for English speakers: French often uses chercher where English uses look for, without needing a separate word for for.

So:

• chercher le moule = to look for the mold/tin

not something like chercher pour le moule.

Because chercher already includes the idea of looking for. In French, the object comes directly after the verb.

So:

• chercher le moule = to look for the mold/tin
• chercher ses lunettes = to look for one’s glasses

English splits the idea into look + for, but French usually does not.

Yes. You can say:

Pendant que je préchauffe le four, Paul cherche le moule.

This means the same thing: While I preheat the oven, Paul is looking for the mold/tin.

The main difference is emphasis. Starting with Pendant que... puts a little more focus on the time relationship or on the speaker’s action first.

It is pronounced roughly like pray-shohf.

A few helpful points:

• pré sounds like pray
• chauffe has the ch sound of sh in French
• au sounds like oh
• the final -e is silent

So préchauffe is approximately pray-shohf.

No, in standard French the subject pronoun is normally required.

So you say:

• je préchauffe
• not just préchauffe in an ordinary statement

French verbs do change form, but not enough for the subject pronoun to be omitted the way it can be in some other languages. The pronoun helps make the sentence clear and natural.