Relative pronouns: el que, quien, las que...

1. What are el / la / los / las que and quien / quienes?

• These are relative pronouns. They connect two sentences and avoid repetition.
• They work like English who, that, which, those who.

Example

• La receta médica con la que voy a la farmacia indica la dosis correcta.
  → “The medical prescription that I take to the pharmacy shows the right dose.”

They point back to a person or thing mentioned (or clear from the context) and give extra information about it.

2. Form: agreement and persons vs. things

• Quien / quienes → only for people.
• El / la / los / las que → for people and things.
• Agreement: el / la / los / las que must match the noun in gender and number.

Examples

• El que tiene cita pasa primero. → “The one (man/person) who has an appointment goes first.”
• Las que llegan tarde deben esperar. → “Those (women/things) that arrive late must wait.”
• Quien no entienda, que pregunte. → “Whoever doesn’t understand should ask.”

3. When do I use el / la / los / las que?

3.1 With a noun already mentioned

Use it instead of repeating the noun, often after a preposition.

• La crema con la que me cuido la piel es hidratante.
  → “The cream with which I look after my skin is moisturizing.”
• Los antibióticos que tomé eran muy fuertes.
  (Here just que is enough. Los que would normally need a preposition or contrast.)

3.2 Without a noun, but clear from context

Use it like English “the one(s) that …”.

• El que está caducado no se puede tomar.
  → “The one that is expired can’t be taken.”
• Las que son sin azúcar están en la estantería de arriba.
  → “The ones that are sugar-free are on the top shelf.”

3.3 With prepositions (a, con, de, para…)

• No encuentro las gafas con las que leo por la noche.
  → “I can’t find the glasses that I read with at night.”
• Los pacientes a los que atiende hoy el doctor Ruiz son extranjeros.
  → “The patients whom Dr. Ruiz is seeing today are foreigners.”

Structure to remember:

• preposition + el / la / los / las + que

4. When do I use quien / quienes?

Only for people. Very similar to English who / those who.

4.1 With a noun (more formal, often between commas)

• El farmacéutico, quien me explicó el tratamiento, fue muy claro.
  → “The pharmacist, who explained the treatment to me, was very clear.”

You could also say:

• El farmacéutico que me explicó el tratamiento… → more neutral / common.

4.2 Without a noun (general “people who…”)

• Quienes tengan náuseas deben consultar al médico.
  → “Those who feel nauseous should see a doctor.”
• Quienes no lean el prospecto pueden tener problemas.
  → “Those who don’t read the leaflet can have problems.”

Here you talk about a group in general, not specific named people.

5. El que or quien for people?

With people, both are often possible. Focus on:

• Formality: quien / quienes sounds more formal / written.
• Prepositions: both are possible. a quien / a quienes is a bit more formal than a el que / a los que.

Typical pairs

• Los pacientes a los que atiende hoy el doctor Ruiz…
  Los pacientes a quienes atiende hoy el doctor Ruiz…
• Conozco a la médica que me atendió ayer.
  Conozco a la médica, quien me atendió ayer. (more formal / written)

In everyday spoken Spanish, que is the most frequent choice. Use quien / quienes when you want a more careful, formal style.

6. Word order: where do I put the pronoun?

Think of this pattern:

1. Antecedent (the noun or “the one(s)”)
2. Preposition (if needed)
3. Relative pronoun
4. Rest of the clause

Patterns to copy

• La paciente a la que atendí antes…
• Los pacientes a los que atiendo hoy…
• Las gafas con las que leo…
• Las personas con quienes trabajo…

Do not put the preposition at the end as in English:

• *La receta que voy a la farmacia con → ❌
• La receta con la que voy a la farmacia → ✅

7. Quick comparison: Spanish vs. English

8. Step‑by‑step decision guide

1. Are you talking about a person or a thing?
   • Person → you can use que, el/la/los/las que, or quien/quienes.
   • Thing → use que or el/la/los/las que, not quien.
2. Is there a preposition before it? (a, con, de, en, para…)
   • Yes → use preposition + el/la/los/las que or preposition + quien/quienes (for people).
   • No → usually simple que is enough. Use quien/quienes if you want a more formal style, especially between commas.
3. Is the noun expressed or omitted?
   • Noun is expressed: la persona que… / el paciente a quien…
   • Noun is omitted ("the one(s) who/that…"): el que… / las que… / quienes…

9. Typical mistakes to avoid

• Using quien for things
  • *La medicina, quien es muy cara, no está incluida. → ❌
  • La medicina, que es muy cara, no está incluida. → ✅
  • La medicina, la que es muy cara, no está incluida. (possible, with contrast) → ✅
• Forgetting agreement with el/la/los/las que
  • *El paciente, las que esperan fuera, está nervioso. → ❌
  • Los pacientes, los que esperan fuera, están nerviosos. → ✅
• Putting the preposition at the end (copying English)
  • *La farmacia que voy a comprar en → ❌
  • La farmacia en la que voy a comprar → ✅

10. Self‑check: do I understand?

Try to answer these questions for yourself:

1. Can I explain in English when to use quien/quienes instead of el/la/los/las que?
2. Can I form structures like a la que, con los que, para quienes without thinking too long?
3. Can I transform “the one(s) who/that …” into Spanish: el que… / la que… / los que… / las que… / quienes…?
4. Can I keep the preposition in front of the pronoun and not at the end of the sentence?

If you are unsure, take 2–3 sentences from your day and rewrite them using:

• el/la/los/las que for things and people.
• quien/quienes for people (formal or “those who…”).

Once you can do that comfortably, you are ready to use these forms in conversation.