Learn Hardcore French: Parfois, elle se trompe et répond à une ancienne annonce. - Sometimes she makes a mistake and answers an old ad.

Elle trompe quelqu’un = She is cheating on / deceiving someone. (direct object)
Elle se trompe = She is wrong / She makes a mistake. (reflexive: she “mistakes herself”)

So if you want the meaning “she makes a mistake,” you must use the reflexive form: se tromper.

What is the function of se in elle se trompe?

Se is the reflexive pronoun for elle (and also for il and on).

It shows that the subject is acting on itself. Grammatically:

Subject: elle
Reflexive pronoun: se
Verb: trompe

Together: elle se trompe = she is mistaken / she makes a mistake.

You must conjugate the verb and keep the reflexive pronoun:

Je me trompe
Tu te trompes
Il / Elle / On se trompe
Nous nous trompons
Vous vous trompez
Ils / Elles se trompent

Why is there no subject again before répond? Why not elle se trompe et elle répond?

In French, when two verbs share the same subject and are joined by et (and), you can repeat the subject or omit it: both are correct.

Parfois, elle se trompe et elle répond à une ancienne annonce.
Parfois, elle se trompe et répond à une ancienne annonce.

The second version simply omits the repeated elle because it’s understood from the first part. This is very common in French, especially in writing.

Why is it répond à and not just répond followed by the noun?

The verb répondre almost always needs à before the thing or person you respond to.

répondre à quelqu’un = to answer someone
répondre à quelque chose = to answer / respond to something

So:

répond à une ancienne annonce = answers an old ad
répond à la question = answers the question
répond à sa mère = answers his/her mother

Without à, the sentence would be incorrect.

What exactly does une ancienne annonce mean? Is it just “an old ad”?

Literally, yes, une ancienne annonce can mean “an old ad,” but there is a nuance because ancienne is placed before the noun.

In French, many adjectives change meaning depending on whether they come:

before the noun (often more figurative or subjective)
after the noun (often more literal/physical)

For ancien / ancienne:

une ancienne annonce (adjective before noun)
- usually: a previous / former ad (no longer current, out of date)
une annonce ancienne (adjective after noun)
- usually: an ad that is old in age, has existed for a long time

In your sentence, context suggests:
elle répond à une ancienne annonce = she answers an outdated / previous ad (probably no longer valid).

Why do we say une ancienne annonce and not un ancienne annonce?

Because annonce is a feminine noun in French: une annonce.

Therefore, the adjective must agree in gender and number with the noun:

Feminine singular: une ancienne annonce
Masculine singular: un ancien journal (an old newspaper)
Feminine plural: de anciennes annonces
Masculine plural: de anciens journaux

So the -e at the end of ancienne matches the feminine noun annonce.

Could I say quelquefois instead of parfois? Do they mean the same thing?

Parfois and quelquefois are very close in meaning: both can mean “sometimes”.

Parfois, elle se trompe…
Quelquefois, elle se trompe…

They are generally interchangeable here.
A few nuances:

Parfois is more common in modern speech.
Quelquefois can sound a bit more formal or old‑fashioned, but it is still correct and used.

So yes, you can say quelquefois instead of parfois in this sentence.

Can I change the word order and say Elle se trompe parfois?

Yes, that is perfectly correct:

Parfois, elle se trompe…
Elle se trompe parfois…

Both mean “Sometimes, she makes a mistake…”

Differences are very slight:

Parfois, elle se trompe puts a bit more emphasis on “sometimes.”
Elle se trompe parfois is more neutral in rhythm.

In everyday French, both patterns are used.

Why is the verb in the present tense? Could this sentence describe a habitual action?

Yes. In French, the present tense is used not only for things happening right now, but also for habitual or repeated actions.

Parfois, elle se trompe et répond à une ancienne annonce.
= She sometimes makes that mistake / does that.

So the French present here is like the English “Sometimes she makes a mistake and answers an old ad.” It describes something that happens from time to time.

Is there a direct object for se tromper in this sentence?

No. In this sentence, se tromper is used without an object; it just means “to be wrong / to make a mistake.”

You can also use se tromper de + noun when you specify what the mistake is about:

Elle se trompe de numéro. = She dials the wrong number.
Je me suis trompé de jour. = I got the day wrong.

But here:

Elle se trompe = She is mistaken (in general), no object needed.

Could I replace à une ancienne annonce with a pronoun?

Yes. The prepositional phrase à une ancienne annonce can be replaced by the pronoun y, which replaces à + thing (not people).

Parfois, elle se trompe et répond à une ancienne annonce.
Parfois, elle se trompe et y répond. = Sometimes she makes a mistake and answers it.

Remember:

y = usually replaces à + noun (thing / place)
It normally goes before the verb:
- Elle y répond.

How would you say the sentence in a more “literal” word‑for‑word English?

A close, fairly literal rendering would be:

“Sometimes, she gets it wrong and responds to a former ad.”

More natural everyday English would be something like:

“Sometimes she makes a mistake and replies to an old ad.”