Marie découvre la culture d'un pays étranger en lisant des livres.

Both découvrir and apprendre relate to gaining knowledge, but they’re not interchangeable.

• Découvrir = to discover, to become aware of something new, to get to know.
  • Marie découvre la culture… suggests she is discovering or getting to know the culture, often gradually and with a sense of exploration.
• Apprendre = to learn (often in a more systematic or factual way).
  • Marie apprend la culture d’un pays étranger would sound like she is learning it in a more formal way (e.g. in a course).

For culture, découvrir is very natural, because it implies exploration and new experiences, not just memorizing facts.

Découvrir is an irregular -ir verb that conjugates like a regular -er verb in the present tense.

Present tense of découvrir:

• je découvre
• tu découvres
• il/elle/on découvre
• nous découvrons
• vous découvrez
• ils/elles découvrent

So in Marie découvre…, Marie = elle, so we use elle découvre.

It is not:

• découvrit → that would be a past historic tense form, not used in everyday speech.
• découvres → that’s the tu form, not the elle form.

French uses articles much more systematically than English.

• la culture d’un pays étranger = the culture of a foreign country
  • la shows we are talking about the culture of that country in general, as a whole concept.

Alternatives change the meaning:

• une culture d’un pays étranger would be odd here; it would sound like one culture among several, which doesn’t fit.
• Leaving out the article (∅ culture) is almost never correct in French in this kind of sentence. French typically requires la, une, de la, etc.

So la culture is the normal way to talk about a country’s culture in a general sense.

d’un is a contraction of de + un.

• de un pays étranger → becomes → d’un pays étranger

We use de here because we are expressing possession or origin:

• la culture d’un pays étranger = the culture of a foreign country

Any time de is followed by un, it contracts to d’un in writing and in speech.

In French, most adjectives come after the noun, not before it.

• un pays étranger = a foreign country
  • pays (noun) + étranger (adjective)

If you said un étranger pays, it would be wrong. Some common adjectives (like grand, petit, beau, bon, mauvais, nouveau, vieux, jeune) often come before the noun, but étranger normally comes after.

The adjective must agree in gender and number with the noun.

• pays is a masculine singular noun in French: un pays
• So the adjective must also be masculine singular: étranger

Forms of étranger:

• masculine singular: étranger
• feminine singular: étrangère
• masculine plural: étrangers
• feminine plural: étrangères

Since pays is masculine singular, the correct form is un pays étranger.

en lisant is en + the present participle of lire (lisant).

It usually means:

• by reading or while reading

So:

• Marie découvre la culture d’un pays étranger en lisant des livres. = Marie discovers the culture of a foreign country by reading books. or …while reading books.

In this construction:

• en + present participle expresses how, by what means, or under what circumstance something happens.

We do not say par lisant. For by doing X in French, the normal form is en + present participle, not par + infinitive.

They express different ideas:

• en lisant des livres:

  • structure: en + present participle
  • meaning: by reading books / while reading books
  • It links an action (reading) as the means or context for another action (discovering).

• être en train de + infinitive:

  • Marie est en train de lire des livres.
  • meaning: Marie is (currently) in the process of reading books (focus on the ongoing action right now).
  • It doesn’t automatically express cause or means; it’s about what she’s doing at the moment.

In your sentence, we want to say she discovers the culture by reading books, so en lisant is the correct structure.

Lisant is the present participle of lire (to read).

Formation of the present participle:

• Take the nous form of the present: nous lisons
• Remove -ons: lis-
• Add -ant: lisant

So:

• lire → nous lisons → lisant

You never add des to form the participle. Des in the sentence belongs to des livres, not to the verb form.

des is the plural indefinite article, roughly some in English.

• des livres = (some) books in general, not specific books.
• In the sentence, it doesn’t matter which books exactly; what matters is that she reads books as a general activity.

Alternatives:

• les livres = the books, specific books already known to speaker and listener.
  • en lisant les livres would suggest certain particular books that have been identified.
• de livres appears after certain quantities or negatives:
  • beaucoup de livres (a lot of books)
  • sans livres (without books, no article)
  • Elle ne lit pas de livres. (She doesn’t read books.)

Here, the idea is general, non-specific books, so des livres is the natural choice.

Yes, you can move the en lisant phrase to the front for emphasis or style:

• En lisant des livres, Marie découvre la culture d’un pays étranger.

This is grammatically correct and quite natural. The meaning is the same:

• She discovers the culture by reading books.

You just have to separate the introductory en lisant clause with a comma.