El copresentador puede entrevistar al oyente y ensayar.

Because the subject is el copresentador, which is third-person singular: he / she / it.

So the verb poder in the present tense must be puede:

• yo puedo = I can
• tú puedes = you can
• él / ella puede = he / she can
• ellos / ellas pueden = they can

Here, el copresentador puede... = the co-host can...

After a modal verb like poder (can / to be able to), Spanish normally uses the bare infinitive directly, just like English after can.

So:

• puede entrevistar = can interview
• puede ensayar = can rehearse / practice

You do not say puede a entrevistar or puede de entrevistar.

Because entrevistar takes a direct object, and when that direct object is a person, Spanish usually adds the personal a.

So:

• entrevistar a alguien = to interview someone

Since el oyente is masculine singular, a + el contracts to al:

• a + el = al

That is why you get:

• entrevistar al oyente

The personal a is the a used before a specific human being (and sometimes pets or personified beings) when that person is the direct object of the verb.

Examples:

• Veo al profesor. = I see the teacher.
• Conozco a María. = I know María.
• Entrevistan al oyente. = They interview the listener.

English does not have this feature, so it often feels unusual to learners at first.

Spanish has only two mandatory contractions of this kind:

• a + el = al
• de + el = del

But:

• a + la stays a la
• de + la stays de la

So:

• entrevistar al oyente
• but entrevistar a la oyente

Oyente is a noun ending in -ente, and many nouns of this type have the same form for masculine and feminine.

So you say:

• el oyente = the male listener / the listener
• la oyente = the female listener

The article tells you the gender, not the noun ending itself.

Yes. Oyente can refer to either a man or a woman.

• el oyente = masculine, or sometimes generic
• la oyente = feminine

In your sentence, al oyente is grammatically masculine. Depending on context, it could mean a male listener or a generic singular listener.

Because one conjugated verb can govern two infinitives joined by y.

So:

• puede entrevistar al oyente y ensayar

means:

• can interview the listener and rehearse

This is completely normal in Spanish, just as in English:

• He can interview the listener and rehearse.

You do not need to repeat puede unless you want extra emphasis.

Not necessarily. Ensayar can be used:

• with an object: ensayar una escena = to rehearse a scene
• without an object when the context makes it clear: ensayar = to rehearse / practice

So in this sentence, ensayar stands on its own. The thing being rehearsed is simply not stated.

In Spain, ensayar often suggests rehearsing something, especially for performance, radio, theatre, music, etc. In some contexts, English practice may also fit.

Because the normal Spanish word for and is y.

It only changes to e before words beginning with an i sound, such as i- or hi-:

• padre e hijo = father and son
• España e Italia

But here the next word is ensayar, which begins with e, not an i sound, so y is correct:

• ...al oyente y ensayar

In normal Spanish, singular countable nouns usually need an article or another determiner.

So el copresentador is natural, while copresentador puede... would normally sound incomplete.

El can mean:

• the specific co-host, if a particular one is meant
• sometimes a generic singular, depending on context

In this sentence, El copresentador is the normal, grammatical subject.

Copresentador means something like co-host or co-presenter.

It is formed from:

• co- = co-
• presentador = presenter / host

The feminine form is:

• copresentadora

So you could also have:

• La copresentadora puede entrevistar al oyente y ensayar.

Yes. You could also say:

• El copresentador puede ensayar y entrevistar al oyente.

That would still be grammatical. The difference is mainly one of focus or natural flow, not basic grammar.

In the original sentence, the speaker presents the actions in this order:

1. entrevistar al oyente
2. ensayar

So the order may reflect the intended sequence or emphasis.