En la excursión éramos veintiséis personas y nadie quiso volver antes de tiempo.

En la excursión sets the scene and means something like on the excursion or during the excursion.

Spanish often uses en with events or situations:

• en la reunión
• en clase
• en el viaje

Here it tells you the context in which the rest happened. You could also say durante la excursión, but en la excursión is very natural.

Because ser is used here to express how many people made up the group.

• Éramos veintiséis personas = the group consisted of twenty-six people / there were twenty-six of us
• Estábamos veintiséis personas sounds wrong in standard Spanish

Estar is usually about location or condition, not group identity/number in this kind of sentence.

Both can talk about quantity, but they are structured differently:

• Éramos veintiséis personas = we were twenty-six people
• Había veintiséis personas = there were twenty-six people

The sentence chooses éramos because the speaker is part of the group. It is a more personal way to say it.

The imperfect often gives background information or describes a situation rather than focusing on a completed action.

Here, éramos veintiséis personas sets the scene:

• that was the size of the group

It is descriptive, not really an event by itself. That is why the imperfect éramos sounds natural.

Not always, but it is very common and sounds natural.

• Éramos veintiséis is possible if the context already makes it clear you are talking about people.
• Éramos veintiséis personas is a little clearer and more explicit.

Spanish often keeps personas after a number when counting people.

Numbers from 16 to 29 are usually written as one word in Spanish:

• dieciséis
• veintidós
• veintiséis
• veintiocho

The accent mark in veintiséis shows the correct stress. The stress falls on the last syllable: veintiséis.

Excursión has the stress on the last syllable: -sión.

Words stressed on the last syllable usually take a written accent if they end in a vowel, n, or s. Since excursión ends in n, it needs the accent mark.

This is a very common past-tense contrast.

• Nadie quiso volver means no one wanted to go back in that specific situation. It presents the desire as a complete fact or decision.
• Nadie quería volver would sound more like no one felt like going back or no one was wanting to go back, with a more ongoing or descriptive feel.

In this sentence, quiso fits because it refers to what happened on that occasion.

Because querer has an irregular preterite stem.

Its preterite forms use quis-:

• quise
• quisiste
• quiso
• quisimos
• quisisteis
• quisieron

So quiso is the correct preterite form, not querió.

Because nadie already makes the sentence negative when it comes before the verb.

• Nadie quiso volver = correct
• No quiso volver nadie = also possible, but different word order
• No nadie quiso volver = incorrect

In Spanish, words like nadie, nada, and nunca do not need no if they come before the verb.

Volver means to return or to go back.

It stays in the infinitive because it follows quiso:

• quiso volver = wanted to go back

This is very common in Spanish:

• quiero salir
• podemos entrar
• decidieron esperar

The first verb is conjugated, and the second stays in the infinitive.

Antes de tiempo means earlier than expected, too early, or before the planned time.

It suggests that there was some expected schedule or normal moment for returning, and nobody wanted to return before that.

It is close to demasiado pronto in some contexts, but antes de tiempo more clearly suggests before the proper time.

Yes, querer + infinitive can sometimes mean to try to in certain contexts, especially with actions that may or may not succeed.

For example:

• Quiso abrir la puerta, pero no pudo = he tried to open the door, but he couldn’t

But in this sentence, nadie quiso volver antes de tiempo is most naturally understood as nobody wanted to go back early, not nobody tried to go back early. The context strongly favors wanted.