Condicionales y verbos modales en inglés: usos, estructuras y ejemplos

Condicionales

1) Zero Conditional

Uso:

Se usa para hechos generales, verdades universales o cosas que siempre suceden.

Estructura:

If + present simple, present simple

Ejemplos:

• If you heat water, it boils.
• If I'm tired, I go to bed early.
• If you mix red and blue, you get purple.

2) First Conditional

Uso:

Situaciones reales y posibles en el futuro.

Estructura:

If + present simple, will + base verb

Ejemplos:

• If it rains, I will stay home.
• If you study, you will pass the exam.
• If we hurry, we will catch the bus.

3) Second Conditional

Uso:

Situaciones improbables en el presente o hipotéticas/fantasía.

Estructura:

If + past simple, would + base verb

Ejemplos:

• If I won the lottery, I would travel the world.
• If she were taller, she would play basketball.
• If we lived near the beach, we would swim every day.

✅ Modal Verbs

Must

Uso: obligación fuerte, regla importante.

Ejemplos:

• You must wear a seatbelt.
• I must finish my homework.

Can

Uso: habilidad, permiso o posibilidad.

Ejemplos:

• I can swim. (habilidad)
• Can I go out? (permiso)
• It can rain today. (posibilidad)

Have to

Uso: obligación externa (por reglas, horarios, alguien más).

Ejemplos:

• I have to wake up early for school.
• She has to take the medicine.

Could

Uso: habilidad pasada, permiso formal, posibilidad leve.

Ejemplos:

• When I was a kid, I could run fast.
• Could I use your phone?
• It could snow tomorrow.

Should

Uso: consejo, recomendación.

Ejemplos:

• You should drink more water.
• He should study for the test.

✅ Condicionales – Formas negativas

1) Zero Conditional (negativo)

Estructura:

If + present simple (negative), present simple (negative)

Uso:

Para hablar de cosas que no suceden si la condición no se cumple.

Ejemplos:

• If you don't water plants, they don't grow.
• If you don't eat, you don't get energy.

2) First Conditional (negativo)

Estructura:

If + present simple (negative), will + not + base verb

Uso:

Hablar de consecuencias negativas en el futuro si la condición no se cumple.

Ejemplos:

• If you don't study, you won't pass the exam.
• If she doesn't hurry, she won't catch the bus.

3) Second Conditional (negativo)

Estructura:

If + past simple (negative), would not + base verb

Uso:

Hablar de situaciones hipotéticas negativas o imposibles en el presente.

Ejemplos:

• If I didn't like music, I wouldn't listen to it every day.
• If they weren't tired, they wouldn't stay home.

✅ Modales – Formas negativas

1) Must → must not (mustn't)

Uso negativo: prohibición fuerte. Algo que no debes hacer.

Ejemplos:

• You mustn't smoke here.
• Students mustn't use phones in class.

2) Can → cannot / can't

Uso negativo: no poder (habilidad), no permiso o imposibilidad.

Ejemplos:

• I can't swim. (no habilidad)
• You can't go out now. (no permiso)
• That can't be true. (imposibilidad)

3) Have to → don't have to / doesn't have to

Uso negativo: significa que NO es necesario, NO tienes obligación. (No es igual a mustn't, que indica prohibición).

Ejemplos:

• You don't have to wake up early tomorrow. (no es necesario)
• She doesn't have to do the homework today.

4) Could → could not (couldn't)

Uso negativo: no poder en el pasado, no permiso, baja posibilidad.

Ejemplos:

• I couldn't walk when I was a baby. (pasado)
• You couldn't enter the club. (no permiso)
• It couldn't be worse. (baja posibilidad / casi imposible)

5) Should → should not (shouldn't)

Uso negativo: dar un consejo negativo.

Ejemplos:

• You shouldn't eat so much junk food.
• He shouldn't stay up late.