Learn Hardcore French: Tant que le riz cuit, nous rangeons les reçus dans l’agenda. - As long as the rice is cooking, we file the receipts in the planner.

tant que = “for as long as” (emphasizes the full duration, sometimes with a faint conditional flavor: “so long as”).
pendant que = “while/whereas” (neutral simultaneity).

In this sentence, both are acceptable. Tant que can suggest you’ll keep tidying for the whole time the rice is cooking. Pendant que sounds a bit more matter-of-fact.

Which tense and mood does French use after tant que?

Use the indicative, not the subjunctive. Match the time frame:

Present time: Tant que le riz cuit, nous rangeons…
Future time: French typically uses the future in both clauses: Tant que le riz cuira, nous rangerons… (Subjunctive is used with other conjunctions like jusqu’à ce que, not with tant que.)

Why is it le riz cuit and not something like “is cooking” with a progressive form?

French doesn’t need a separate progressive tense. The simple present covers “is cooking.”

Neutral: Le riz cuit.
If you want to stress the ongoing process: Le riz est en train de cuire.
Don’t say Le riz est cuit unless you mean “The rice is cooked/done.”

Is cuit here a verb or an adjective?

Here it’s the verb cuire, 3rd person singular present indicative: (le riz) cuit = “(the rice) is cooking.”

Past participle/adjective: cuit(e)(s) appears with auxiliaries or with être for a result: Le riz est cuit = “The rice is cooked.”

Could I use cuisiner instead of cuire?

Different meanings:

cuire = to cook in the sense of undergoing/delivering the cooking process (the food “cooks”): Le riz cuit.
faire cuire = to cook something (causative, very common): Nous faisons cuire le riz.
cuisiner = to cook/prepare food generally: Nous cuisinons (we’re cooking), but you don’t normally say cuisiner le riz to mean “cook rice” in this mechanical sense.

Why nous rangeons and not on range?

Both mean “we,” but:

nous is standard/formal (and required in writing when you want explicit 1st person plural agreement).
on is more common in speech and informal writing: Tant que le riz cuit, on range les reçus…

What exactly does ranger mean? Is it a false friend with “arrange”?

ranger = to tidy up, put away, organize: ranger les reçus = “file/put away the receipts.”
arranger = to arrange, fix, sort out (make something suitable), not “to tidy” in the house-keeping sense.

Why is it spelled rangeons with an extra “e”?

To keep the soft “g” sound (/ʒ/). After “g,” adding “e” before “-ons” gives the soft sound: nous mangeons, nous rangeons. Without the “e” (rangons), the “g” would be hard (/g/).

Does reçus mean “received,” or does it mean “receipts”?

Both exist, but here it’s the noun un reçu (plural des reçus/les reçus) = “a receipt.”

As a past participle/adjective: reçu(s)/reçue(s) = “received/accepted,” agreeing in gender/number.
Noun gender: un reçu is masculine, so plural “receipts” is les reçus (not “les reçues”).

Any spelling tips for reçus?

The cedilla in ç keeps the “s” sound before “u.” Without it, “rcus” would have a hard “k” sound.
No circumflex on the “u” here: reçu (not reçû). Compare with dû (owed), which does take a circumflex.

Is agenda a false friend?

Yes. In French, un agenda is a diary/planner/datebook (the object you carry). In English, “agenda” is usually a list of topics. For “agenda” in the meeting sense, French uses l’ordre du jour. So dans l’agenda = “in the planner.”

Why dans l’agenda and not sur l’agenda or something else?

dans l’agenda = physically inside the planner (e.g., slipped into a pocket).
sur l’agenda in the figurative English sense “on the agenda” corresponds to French à l’ordre du jour (or à l’agenda in Canadian French usage).
If you mean “on the calendar,” say sur le calendrier (for a wall calendar) or dans l’agenda (for a personal planner).

Why is it l’agenda and not le agenda?

Elision: le or la becomes l’ before a vowel sound. agenda starts with a vowel, so l’agenda is required.

Is the comma after the first clause required? Can I move the clause?

With the subordinate clause first, a comma is standard: Tant que le riz cuit, …
You can flip the order (often without a comma): Nous rangeons les reçus dans l’agenda tant que le riz cuit.

Pronunciation tips?

Approximate guide:

Tant [tɑ̃] (nasal “an”)
que [kə]
le riz [lə ʁi]
cuit [kɥi] (the “ui” is like saying “k” + French “huit” start)
nous rangeons [nu ʁɑ̃ʒɔ̃] (soft “g” = [ʒ]; nasal “on” = [ɔ̃])
les reçus [le ʁəsy] (no liaison “z” before the “r” of reçus)
dans l’agenda [dɑ̃ laʒɛ̃da] (soft “g” in agenda; nasal vowels in dans/agenda)

Could I make it sound more natural differently?

Depending on context:

If you mean “while the rice is cooking (right now), we’re tidying”: your sentence is fine, or use Pendant que le riz cuit, nous rangeons…
If it’s a plan about the future: Pendant que le riz cuira, nous rangerons les reçus…
If you mean “we usually tidy receipts whenever rice is cooking”: the present works as a habitual. You could add an adverb for clarity: D’habitude, tant que le riz cuit, nous rangeons…