O telão mostra o repertório.

Telão usually means a big screen, such as a projection screen, giant display, or jumbotron-style screen at an event.

It comes from tela (screen) plus the augmentative ending -ão, which often gives the idea of big or large. So telão is not just any screen, but specifically a noticeably large one.

That is a very common learner question.

The base word is a tela, but the augmentative form here is o telão, which is masculine. In Portuguese, when words change with augmentative endings like -ão, the gender does not always stay the same as the original word.

So the safest approach is:

• learn a tela
• learn o telão

as separate vocabulary items.

Portuguese uses definite articles more often than English does.

In this sentence:

• O telão = the big screen
• o repertório = the repertoire / the set list / the program

This often sounds natural in Portuguese when the speaker means a specific thing that is understood from the situation. English might sometimes omit the where Portuguese keeps it, but here both articles are completely normal.

Because mostra is the conjugated form of the verb mostrar (to show).

Here the subject is o telão, which is third-person singular, so in the present tense you get:

• eu mostro = I show
• você/ele/ela mostra = you/he/she/it shows

So O telão mostra o repertório uses the correct present-tense form: the big screen shows ...

Because mostrar normally takes a direct object.

So:

• mostrar algo = to show something
• mostrar o repertório = to show the repertoire

No preposition is needed before o repertório here.

Repertório can mean the repertoire, but in real-life contexts it often refers more naturally to:

• a performer’s or group’s set list
• the selection of songs/pieces
• the program of works being presented

So in a concert, event, or performance setting, repertório often means the material being performed.

Yes. Mostrar is a very flexible verb. Depending on context, it can mean:

• show
• display
• reveal
• indicate

In this sentence, because the subject is a screen, English might naturally say:

• shows
• displays

Both fit the idea well.

They are important.

In telão:

• ã marks a nasal sound
• the stress falls on the last syllable: te-LÃO

In repertório:

• the acute accent in ó marks the stressed syllable
• the stress falls on TÓ: re-per-TÓ-rio

So the accent marks help you know where the word is stressed, and in telão the tilde also changes the vowel quality.

A rough English-friendly guide would be:

oh teh-LOWN MOHS-trah oo heh-pehr-TOH-ryoo

A few notes:

• ão in telão is nasal, so it is not exactly like English own
• the r at the beginning of repertório often sounds like an English h in many Brazilian accents
• the r in the middle can sound like a quick tap

This is only an approximation, but it helps with the rhythm and stress.

This sentence uses the most neutral and common word order in Portuguese:

subject + verb + object

• O telão = subject
• mostra = verb
• o repertório = object

Portuguese can sometimes change word order for emphasis, but O telão mostra o repertório is the normal, natural version.

Yes, but it changes the meaning slightly.

• A tela = the screen
• O telão = the big screen

So A tela mostra o repertório is grammatically correct, but it does not carry the same idea of a large display. If the original situation involves a giant event screen, telão is the better choice.