Empieza exactamente a las ocho.

Empieza comes from the verb empezar, meaning to begin or to start.

Here it is:

• 3rd person singular
• present indicative

So it can mean:

• he/she starts
• it starts
• you start (formal usted)

In this sentence, it most naturally means it starts.

Also note the stem change:

• empezar
• empiezo, empiezas, empieza...

So the e changes to ie in many present-tense forms.

Spanish often leaves out subject pronouns when they are clear from the verb form or the context.

So instead of saying something like Ello empieza exactamente a las ocho, Spanish simply says:

• Empieza exactamente a las ocho.

The verb empieza already tells you it is he/she/it/you (formal). In real context, you usually know what is being talked about: a film, a class, a meeting, a show, etc.

Spanish uses a + article + time when saying that something happens at a certain time.

So:

• a la una = at one
• a las dos = at two
• a las ocho = at eight

This is the normal pattern for clock times.

Because clock times in Spanish are based on the understood word horas, which is feminine:

• las ocho (horas)

Since horas is feminine plural, Spanish uses las.

That is why you say:

• la una
• las dos
• las tres
• las ocho

Because una is singular, while dos, tres, ocho, etc. are plural in this structure.

So:

• a la una = at one
• a las ocho = at eight

This matches the understood noun hora/horas:

• a la una (hora)
• a las ocho (horas)

It can refer to a scheduled future event.

In Spanish, just like in English, the present tense is often used for timetables and scheduled events:

• The train leaves at six.
• Empieza exactamente a las ocho.

So even though empieza is grammatically present tense, the meaning may be future depending on context:

• a film tonight
• a class tomorrow
• a meeting later today

Exactamente means exactly. It adds precision.

So the sentence does not just mean that something starts at eight; it means it starts exactly at eight, with no delay or approximation.

It modifies the idea of the starting time very naturally here.

Yes, Spanish adverbs often have some flexibility.

The most natural version here is:

• Empieza exactamente a las ocho.

But you may also hear:

• Empieza a las ocho exactamente.

That also works, though it can sound slightly more emphatic or stylistically different depending on context.

The version with exactamente before a las ocho is very standard and smooth.

Yes. Comienza from comenzar also means starts/begins.

So these are both correct:

• Empieza exactamente a las ocho.
• Comienza exactamente a las ocho.

In many contexts, they are interchangeable. Empezar is extremely common in everyday speech. Comenzar can sound a little more formal or a little more written, but both are normal.

Yes, but in this sentence it most naturally refers to an event, activity, or programme.

For example, it could refer to:

• a class
• a film
• a concert
• a meeting
• a match

If the context were a person, empieza could mean he/she starts, for example:

• Empieza exactamente a las ocho = He/She starts exactly at eight

But without context, English speakers usually understand it here as It starts exactly at eight.

Because Spanish uses a for clock times.

So:

• a las ocho = at eight

Using en here would be incorrect for telling the time of an event.

English learners sometimes expect a direct match with in/on/at, but Spanish has its own pattern, and with clock time the normal preposition is a.

In standard Spain pronunciation, empieza is roughly:

• em-PYE-tha

More precisely:

• em as in a short em
• pie like pye
• za in Spain sounds like tha because z is pronounced with the th sound of thin

So in Spain:

• empieza ≈ em-PYE-tha

If you hear Latin American Spanish, you will usually hear:

• em-PYE-sa

Both are correct in their own varieties, but for Spain the th sound is expected.

Not exactly.

• en punto means on the dot or o’clock exactly
• exactamente means exactly

For this sentence, both can fit, but they are not always identical in nuance.

Examples:

• Empieza a las ocho en punto. = It starts at eight on the dot.
• Empieza exactamente a las ocho. = It starts exactly at eight.

En punto is especially common with whole-hour times. Exactamente is more general and can be used in many kinds of precise statements.

A few common points:

1. No subject pronoun

   • Spanish often omits it/he/she.

2. Present tense for scheduled future

   • Empieza may refer to something that will happen later.

3. Time expression

   • Spanish says a las ocho, not something that literally matches every English pattern word for word.

4. Article with time

   • You need las with most times: a las dos, a las ocho, a las diez.

5. Stem change

   • empezar becomes empieza, not empeza.

So although the sentence is short, it contains several very typical Spanish patterns.