Quand le soleil est bas, je ferme le rideau.

Quand means when, and it introduces a time clause.

In this sentence, Quand le soleil est bas sets the situation or time frame first, and then je ferme le rideau gives the main action.

You could also say Lorsque le soleil est bas, je ferme le rideau, but quand is more common in everyday French.

French usually keeps a straightforward subject + verb + complement order:

• le soleil = subject
• est = verb
• bas = complement/adjective

So le soleil est bas follows the normal French pattern, just like the sun is low in English.

Here, bas is an adjective, not an adverb.

It describes the subject le soleil, so est bas means is low.

Because soleil is masculine singular, the adjective stays bas. If the noun were feminine singular, it would change:

• La lune est basse.

So the form bas agrees with le soleil.

Bas and en bas are related, but they are not used the same way.

• être bas = to be low
• être en bas = to be down below / downstairs / at the bottom

So in this sentence, le soleil est bas is correct because it describes the sun’s position in the sky as low.

If you said Le soleil est en bas, it would sound strange, as if the sun were literally down below somewhere.

French often uses the present tense for:

• general truths
• repeated actions
• habits
• things that happen whenever a condition is met

So Quand le soleil est bas, je ferme le rideau means something like:

• When the sun is low, I close the curtain
• or more naturally, Whenever the sun is low, I close the curtain

This is a normal use of the present tense in French.

In this kind of sentence, it often has a whenever sense.

Because both parts are in the present tense, the sentence sounds like a repeated habit, not just one single event.

So even though quand literally means when, the whole sentence can naturally be understood as:

• Whenever the sun is low, I close the curtain.

In standard French, you normally need the subject pronoun.

So you say:

• je ferme
• not just ferme

Unlike English imperatives such as Close the curtain, this is a normal statement, so French needs the subject.

French verb endings help, but they usually do not replace the subject pronoun in ordinary speech or writing.

French usually uses an article where English sometimes does not.

So le rideau is normal because French wants a determiner before most singular countable nouns.

You would not normally say just je ferme rideau.

The article le can mean:

• the curtain
• or sometimes just the relevant curtain in the situation

French can use either singular or plural, depending on the real situation.

• le rideau = the curtain
• les rideaux = the curtains

In this sentence, the speaker is thinking of one curtain, or one window covering treated as a single object.

If there are two curtains, you could say:

• Quand le soleil est bas, je ferme les rideaux.

So the singular is not a grammar rule here; it is just the chosen noun.

Yes, possibly, depending on the exact action.

• fermer le rideau focuses on the result: the curtain is closed
• tirer le rideau focuses more on drawing or pulling the curtain

Both can be natural, but they are not always identical in feel.

If you want the simplest, safest version for close the curtain, fermer le rideau is a very good choice.

The comma is normal and helpful when the quand clause comes first.

So this is very standard:

• Quand le soleil est bas, je ferme le rideau.

If the main clause came first, the comma is often omitted:

• Je ferme le rideau quand le soleil est bas.

Both are correct; the comma mainly reflects the sentence structure and makes it easier to read.

A careful pronunciation would be approximately:

Kahn luh soh-lay eh bah, zhuh fehrm luh ree-doh.

A few useful points:

• quand: the d is silent
• soleil sounds roughly like so-lay
• est is pronounced like eh
• bas: the s is silent
• je sounds like zhuh
• rideau sounds roughly like ree-doh

In natural speech, je is often reduced, so je ferme may sound closer to j’ferme.