Es importante terminar la obra en la cocina antes del sábado.

Because es importante is the normal full way to say it is important in Spanish.

• Es = it is
• importante = important

Spanish often uses es + adjective + infinitive for general statements:

• Es fácil aprender. = It is easy to learn.
• Es necesario salir temprano. = It is necessary to leave early.

Saying only Importante would sound incomplete here.

After expressions like es importante, Spanish often uses an infinitive when speaking generally about an action.

So:

• Es importante terminar la obra... = It is important to finish the work...

This structure is very common:

• Es bueno comer bien. = It is good to eat well.
• Es difícil encontrar aparcamiento. = It is difficult to find parking.

If you want to say that a specific person or group should do it, Spanish often uses que + subjunctive instead:

• Es importante que terminemos la obra... = It is important that we finish the work...
• Es importante que terminen la obra... = It is important that they finish the work...

In Spain, la obra very often means building work, renovation work, or construction work, especially in a home.

So in this sentence, la obra en la cocina most likely means:

• the renovation in the kitchen
• the construction work in the kitchen
• the building work being done in the kitchen

This is a very Spanish usage. In everyday Spain Spanish, hacer obras means to do renovations or building work.

Examples:

• Estamos de obras. = We are having work done / We are under renovation.
• La obra del baño va lenta. = The bathroom renovation is going slowly.

Because la obra is the direct object of terminar, so no preposition is needed.

• terminar algo = to finish something

So:

• terminar la obra = to finish the work
• terminar el proyecto = to finish the project
• terminar la tarea = to finish the homework/task

English learners sometimes want to add de, but that is not how terminar works when it means finish something.

Be careful: terminar de + infinitive is a different structure:

• Termino de comer. = I finish eating / I have just finished eating
  depending on context

But here we have terminar + noun, so it is simply terminar la obra.

Spanish normally uses the definite article with rooms of a house:

• en la cocina = in the kitchen
• en el baño = in the bathroom
• en el salón = in the living room

In English, we also usually say in the kitchen, so this matches well.

Dropping the article here would sound unnatural.

Mostly it tells you where la obra is: the work/renovation is in the kitchen.

So the most natural interpretation is:

• the kitchen work/renovation
• the work being done in the kitchen

Grammatically, it follows la obra, so it is understood as describing that noun.

You could think of it as:

• terminar [la obra en la cocina] antes del sábado

rather than:

• [terminar] en la cocina

Because antes de is followed here by the noun phrase el sábado.

When de and el come together, they contract:

• de + el = del

So:

• antes de el sábado becomes antes del sábado

This contraction is mandatory in standard Spanish.

Compare:

• antes del examen = before the exam
• antes del verano = before the summer

But there is no contraction with la:

• antes de la cena = before dinner
• not dela

Literally, it means before Saturday.

So the most direct meaning is that the work should be finished before Saturday begins.

In real-life usage, English may sometimes translate this kind of deadline idea as by Saturday, but antes del sábado is more strictly before Saturday.

If Spanish wanted to express by Saturday more directly, you might also hear:

• para el sábado = by Saturday / for Saturday

So there is a small nuance:

• antes del sábado = before Saturday
• para el sábado = by Saturday / ready for Saturday

Because this sentence is impersonal and general. It focuses on the importance of the action, not on who does it.

• Es importante terminar la obra... = It is important to finish the work...

This is similar to English, where you can also leave the subject vague.

If you want to mention who needs to do it, Spanish can make that explicit:

• Es importante que terminemos la obra... = It is important that we finish the work...
• Es importante que terminen la obra... = It is important that they finish the work...

Yes, but there are slight differences in style and frequency.

• terminar = very common, neutral
• acabar = also very common
• finalizar = more formal or administrative

Possible alternatives:

• Es importante acabar la obra en la cocina antes del sábado.
• Es importante finalizar la obra en la cocina antes del sábado.

In everyday speech in Spain, terminar and acabar are generally more natural than finalizar.

Importante is an adjective, but it has the same form for masculine and feminine singular.

So:

• Es importante = It is important
• La obra es importante = The work is important
• El proyecto es importante = The project is important

Only the plural changes:

• Es importante terminar... = singular idea
• Son importantes estos cambios. = These changes are important

So importante is one of those adjectives that does not change between masculine and feminine.

Yes. A very common alternative is:

• Es importante que se termine la obra en la cocina antes del sábado.

This means something like:

• It is important that the work in the kitchen be finished before Saturday.

Why the subjunctive?

Because es importante que... expresses a judgment, recommendation, or necessity, and that often triggers the subjunctive.

Compare the two structures:

• Es importante terminar la obra...
  General, impersonal, action-focused
• Es importante que se termine la obra...
  More clause-based, often a bit more formal or explicit

Both are correct.

Yes, it is very natural.

The sentence is built like this:

• Es importante — introductory evaluation
• terminar la obra — the action
• en la cocina — location of the work
• antes del sábado — time limit

Spanish word order is fairly flexible, but this version sounds standard and clear.

You could move parts for emphasis, for example:

• Es importante terminar antes del sábado la obra en la cocina.

But that sounds a little less neutral. The original sentence is the most straightforward everyday version.

Depending on context, a natural English translation could be:

• It’s important to finish the work in the kitchen before Saturday.
• It’s important to finish the kitchen renovation before Saturday.
• It’s important to finish the building work in the kitchen before Saturday.

If la obra clearly means renovation, kitchen renovation is often the most natural English choice.