Learn Hardcore Spanish (Spain): Mi amiga es capaz de subir diez pisos sin ascensor. - My friend is capable of climbing ten floors without an elevator.

Es capaz de + infinitive literally means “is capable of” or “has the capacity to.” It often emphasizes someone’s potential or ability under challenging circumstances.
Poder + infinitive (for example, puede subir) simply states “can” or “is allowed to”, and is more neutral.
Example comparison:

Ella es capaz de correr un maratón. (She’s capable of running a marathon—emphasis on capacity.)
Ella puede correr un maratón. (She can run a marathon—neutral statement of ability.)

Why is there a de after capaz?

In Spanish, capaz requires the preposition de when it’s followed by an infinitive. The pattern is always ser capaz de + infinitive, so the de is mandatory and connects capaz to the verb that follows.

Why isn’t there an article before diez pisos?

When you directly specify a quantity in Spanish, you usually omit the article.

diez pisos = “ten floors” without an article.
If you wanted to say “the ten floors,” you’d need an article: los diez pisos.

How does subir work with diez pisos? Does it require a preposition?

Here subir takes diez pisos as a direct object, meaning “to climb/go up ten floors.” No preposition is needed.
If you specify a destination rather than a number of levels, you use a:

subir a la azotea (to go up to the rooftop)
But for counting floors, it’s simply subir + number + pisos.

Why is there no article after sin in sin ascensor? Could we use one?

After sin (meaning “without”), Spanish normally omits the indefinite article when talking about lacking something in general:

sin ascensor = “without an elevator.”
You can say sin un ascensor if you want to stress “without a single elevator,” or sin el ascensor if referring to a specific one, but the bare noun is most common for general absence.

What does ascensor mean? Are there other synonyms in different regions?

In Spain ascensor means “elevator.” Common regional variants include:

Latin America: elevador
Formal/technical: montacargas (usually for freight)
Remember, escalera mecánica = “escalator.”

Can we move sin ascensor within the sentence without changing the meaning?

Yes, Spanish allows some flexibility, but word order affects emphasis.

Original: Mi amiga es capaz de subir diez pisos sin ascensor. (neutral)
Fronted: Sin ascensor, mi amiga es capaz de subir diez pisos. (emphasizes lack of elevator)
Mid-sentence: Mi amiga, sin ascensor, es capaz de subir diez pisos. (more literary or formal)

Can we replace es capaz de with puede? Are they interchangeable?

Yes, you can say Mi amiga puede subir diez pisos sin ascensor, and the core meaning stays the same.
Nuance:

puede = straightforward “can.”
es capaz de = highlights capacity/potential, sometimes implying effort or overcoming difficulty.

Does piso in Spain always mean floor, or can it also mean apartment?

In Spain, piso can mean both “floor” (story of a building) and “flat/apartment.” Context tells you which:

subir diez pisos → floors
alquilar un piso → apartment

Why is it mi amiga rather than mi amigo?

Spanish nouns and adjectives agree in gender with the person they describe.

A female friend is mi amiga.
A male friend would be mi amigo.
Always match -a for feminine, -o for masculine (and watch out for irregular endings).