Learn Spanish (Latin America): La pregunta es muy complicada.

Muy means "very" and is used right before adjectives (like complicada) and adverbs. You would use mucha (a lot / much) if you were talking about a noun, like mucha tarea (a lot of homework). Since we are saying how complicated the question is, we need muy.

Wait, isn't pregunta a verb? I thought it meant "he/she asks".

It can be! Pregunta is the "he/she/it" form of the verb preguntar (to ask). However, in this sentence, it has the word la (the) in front of it, which tells us it is being used as a noun: la pregunta (the question). It is very common in Spanish for nouns and verb forms to look exactly the same.

Why does complicada end in an -a?

In Spanish, adjectives always have to match the gender and number of the noun they describe. Because la pregunta is a feminine, singular noun, the adjective describing it must also be in its feminine, singular form: complicada (instead of the masculine complicado).

Why use es instead of está for "is very complicated"?