Todavía tengo que firmar el anexo del contrato antes de salir de la oficina.

Todavía means still / yet here. It shows that the action has not happened yet, but it is still pending.

So Todavía tengo que firmar... means something like:

• I still have to sign...
• I haven’t signed it yet; I still need to do it

Putting todavía near the beginning is very natural because it sets the situation right away.

A close synonym is aún:

• Aún tengo que firmar...

Both are correct, though todavía is very common in everyday speech.

Spanish often omits subject pronouns because the verb ending already shows who the subject is.

• tengo = I have

So (yo) tengo que firmar is understood automatically.

You could say:

• Yo todavía tengo que firmar el anexo...

But adding yo usually gives extra emphasis, contrast, or clarity. In a neutral sentence, leaving it out is more natural.

Tener que + infinitive means to have to do something.

Here:

• tengo que firmar
• literally: I have to sign

This is one of the most common ways to express obligation in Spanish.

More examples:

• Tengo que estudiar. = I have to study.
• Tenemos que irnos. = We have to leave.

Do not confuse it with hay que, which means one has to / it is necessary to in a more general, impersonal sense.

• Tengo que firmar el anexo. = I have to sign the annex.
• Hay que firmar el anexo. = The annex has to be signed / One has to sign the annex.

Because after tener que, Spanish uses an infinitive.

Structure:

• tener que + infinitive
• tengo que firmar
• tienes que salir
• tenemos que hablar

This is exactly like English have to + base verb:

• I have to sign
• You have to leave

So firmar stays in its dictionary form because the conjugated part is tengo.

In this context, anexo usually means an attachment, appendix, annex, or additional document attached to a contract.

So el anexo del contrato is most naturally:

• the annex to the contract
• the contract attachment
• the appendix to the contract

In legal or administrative contexts, anexo is very common.

A learner should note that Spanish anexo does not always match one single English word perfectly; the best translation depends on context.

Because de + el contracts to del in Spanish.

So:

• de + el contrato → del contrato

This contraction is mandatory in normal Spanish.

Compare:

• el anexo del contrato = the annex of the contract
• la firma del director = the director’s signature

Important exception: If El is part of a proper name, it usually does not contract.

• de El Escorial
  not del Escorial when referring to the official name

But in ordinary noun phrases like el contrato, you must use del.

Spanish usually shows possession or relationship with de.

So:

• el anexo del contrato
• literally: the annex of the contract

English often prefers:

• the contract annex
• the annex to the contract
• the contract’s annex

Spanish does not use an apostrophe-s structure like English. Instead, it normally uses de.

Because after antes, Spanish normally uses de before an infinitive.

So the pattern is:

• antes de + infinitive

Examples:

• antes de comer = before eating
• antes de dormir = before sleeping
• antes de salir = before leaving

This is a very common structure and should be learned as a fixed pattern.

Because antes de + infinitive is used when the subject is the same as the subject of the main verb.

Here, the person who has to sign is also the person who leaves. So Spanish uses the infinitive:

• Todavía tengo que firmar... antes de salir...

If the subject changes, Spanish usually uses a different structure, often with que + a conjugated verb:

• Tengo que firmar el anexo antes de que salga el mensajero.
• I have to sign the annex before the courier leaves.

So:

• same subject → antes de + infinitive
• different subject → often antes de que + subjunctive

Yes. Salir de means to leave / go out of / exit a place.

So:

• salir de la oficina = to leave the office

The preposition de is required with salir when you mention the place you are leaving.

More examples:

• salir de casa = to leave home
• salir del coche = to get out of the car
• salir de la reunión = to leave the meeting

So you should think of salir de as a set combination.

Spanish often uses the definite article (el, la, los, las) in places where English might use a possessive like my or the, depending on context.

Here, la oficina simply means the office, and in many situations it is understood as the office I’m in / my workplace / the office we’re talking about.

Spanish does not always specify possession if the context already makes it clear.

So all of these could be possible depending on context:

• antes de salir de la oficina = before leaving the office
• antes de salir de mi oficina = before leaving my office

The version with la oficina is broader and more neutral.

It is grammatically present tense, but the meaning points to something that still needs to happen, so it refers to a present obligation about a future action.

• Tengo que firmar does not mean I am signing
• it means I have to sign / I need to sign

This is completely normal in both Spanish and English.

So the timeline is:

1. right now: the obligation exists
2. later: the signing will happen
3. it must happen before leaving the office

Yes.

• Aún tengo que firmar el anexo del contrato...
• Me queda por firmar el anexo del contrato...

Both are natural, but they are slightly different in feel.

Aún / todavía tengo que firmar
This focuses on the fact that the task is still pending.

Me queda por firmar...
This sounds more like I still have left to sign... It highlights an item remaining on a to-do list.

The original sentence with todavía is very straightforward and common.

The sentence is structured like this:

• Todavía = still
• tengo que firmar = I have to sign
• el anexo del contrato = the annex of the contract
• antes de salir de la oficina = before leaving the office

So the full order is:

still + I have to sign + the contract annex + before leaving the office

This word order is very natural in Spanish. It starts with the idea of unfinished business (todavía), then gives the obligation, then the object, and finally the time condition.

It sounds completely natural as it is.

In speech, a speaker from Spain might stress todavía or antes de salir depending on what they want to emphasize:

• Todavía tengo que firmar el anexo del contrato...
  emphasis on the fact it is still pending

• ...antes de salir de la oficina.
  emphasis on the deadline

A slightly more conversational version could also be:

• Todavía me falta firmar el anexo del contrato antes de salir de la oficina.

But the original sentence is perfectly idiomatic and clear.