La leçon a vingt pages.

No. In La leçon a vingt pages, a is the verb avoir in the third-person singular: has.

• avoir = to have
• il/elle/on a = he/she/it has

So here, La leçon a... = The lesson has...

This is different from à, which is a preposition often meaning to, at, or in.

• a = a verb form of avoir
• à = a preposition

The accent mark makes them different words.

French usually uses an article where English often can omit one.

So French prefers:

• la leçon = the lesson

rather than just leçon by itself.

This is very common. In full sentences, French nouns usually come with an article or another determiner such as:

• la leçon = the lesson
• une leçon = a lesson
• ma leçon = my lesson
• cette leçon = this lesson

Yes. Leçon is a feminine noun in French.

That is why it takes the feminine singular article la:

• la leçon = the lesson

If it were masculine, it would use le instead.

Grammatical gender in French does not always match any logical real-world gender. You simply have to learn each noun with its gender.

A good habit is to memorize nouns with their article:

• la leçon
• le livre
• la page

Yes. French uses avoir very naturally for things that contain or consist of a certain number of parts.

So La leçon a vingt pages is completely normal French.

It works much like English:

• The book has 300 pages.
• The house has three bedrooms.
• The lesson has twenty pages.

French does the same:

• Le livre a 300 pages.
• La maison a trois chambres.
• La leçon a vingt pages.

No, not in standard French.

You cannot normally use être by itself that way for this meaning.

The natural sentence is:

• La leçon a vingt pages.

You may also sometimes hear or see:

• La leçon est longue de vingt pages.
• La leçon est de vingt pages.

But for a learner, the safest and most natural basic pattern is:

• X a vingt pages = X has twenty pages

Because there are twenty of them.

In French, nouns usually become plural by adding -s:

• une page = one page
• des pages = pages

So:

• vingt pages = twenty pages

Even though the -s is written, it is usually not pronounced here.

Yes. Page is also a feminine noun:

• une page
• la page

In your sentence, you see pages in the plural, so the gender is not very visible there. But if it were singular, you would say:

• La leçon a une page.

Both leçon and page are feminine nouns.

The word order is very close to English:

• La leçon = subject
• a = verb
• vingt pages = object/complement

So it follows a basic Subject + Verb + Object/Quantity pattern:

• La leçon a vingt pages.

This is one reason the sentence is quite beginner-friendly.

Leçon is pronounced approximately like:

• luh-son with a nasal final sound

A more precise guide is:

• leçon ≈ luh-SOHN (nasal, not a fully pronounced English n)

Important detail: the ç is a cedilla. It makes the c sound like s before o.

So:

• leçon sounds with an s sound, not a k sound

Without the cedilla, lecon would suggest a different pronunciation pattern, so the ç matters.

A careful pronunciation is approximately:

la luh-SOHN a van pazh

A few notes:

• la = lah
• leçon = luh-SOHN with a nasal ending
• a = ah
• vingt = van (nasal; the final t is not pronounced here)
• pages = pazh (final s is silent)

So the whole sentence is roughly:

lah luh-SOHN ah van pazh

In vingt pages, the final t of vingt is normally silent because the next word begins with a consonant sound: pages.

So:

• vingt pages → vingt sounds like van (nasal)

But in some other contexts, especially before a vowel sound, you may hear the t pronounced:

• vingt euros

So for this sentence, pronounce it as:

• vingt pages → no pronounced final t

It contains both a singular noun and a plural noun:

• La leçon is singular: one lesson
• pages is plural: twenty pages

That is completely normal. The lesson is one thing, but it contains many pages.

So the verb is singular too:

• La leçon a... not
• La leçon ont...

because the subject is la leçon, not pages.

Yes.

• La leçon a vingt pages. = The lesson has twenty pages.
• Une leçon a vingt pages. = A lesson has twenty pages.

So changing the article changes the meaning from the to a/an.

This is a very useful pattern:

• La page... = the page
• Une page... = a page
• Le livre... = the book
• Un livre... = a book