Quién means who or whom, it changes to quiénes in the plural.
¿Sabes quién es ese hombre? (Do you know who this man is?)
¿Quién quiere ser millonario? (Who wants to be a millionaire?)
¿Quiénes son estos hombres? (Who these men are?)
¿A quién conoces en Buenos Aires? (Who do you know in Buenos Aires?)
Cuánto means how, how much, how many and can be used in three ways.
- With a verb, i.e. as an adverb. It doesn’t change to agree with anything:
¿Cuánto cuesta? (How much does it cost?)
- With a noun, i.e. as an adjective, so it has to agree with the noun in gender and number as any other adjective ending in –o.
¿Cuánto dinero tienes? (How much money do you have?)
¿Cuánta agua hay en la nevera? (How much water is in the fridge?)
¿Cuántos hijos tienes? ¿How many children do you have?)
¿Cuántas personas hay en la fiesta? (How many people are in the party?)
- Instead of a noun, i.e. as a pronoun, so it has to agree with the noun it replaces:
Vino: ¿cuánto quieres? (Wine: how much would you like?)
Cerveza: ¿cuánta quieres? (Beer: how much would you like?)
Helados: ¿cuántos quieres? (Ice-creams: how many would you like?)
Naranjas: ¿cuántas quieres? (Oranges: how many would you like?)
Practice 1: Choose the question word (general revision)
Practice 2: Choose the question word (general revision)
Practice 3: Write the question word (general revision)