Colgué un espejo enorme para reflejar más luz en el cuarto.

Because colgar is a verb ending in -gar, and in the yo form of the preterite, verbs like this change g to gu before é to keep the hard g sound.

• colgar → colgué
• Compare:
  • pagar → pagué
  • llegar → llegué

If it were colgé, Spanish speakers would pronounce the g differently. The u is there just to preserve the sound.

Colgué is the first-person singular preterite: I hung.

The preterite is used because the sentence describes a completed action in the past: the speaker hung the mirror at a specific moment.

So:

• colgué = I hung
• not colgaba = I was hanging / I used to hang

If the focus were on an ongoing background action, Spanish might use the imperfect, but here it is a finished event.

Spanish often leaves out subject pronouns because the verb ending already shows who is doing the action.

• colgué already means I hung
• So yo colgué is possible, but usually unnecessary

You would add yo only for emphasis, contrast, or clarity:

• Yo colgué el espejo, no mi hermano.

Because espejo is a masculine noun, so it takes un.

• el espejo
• un espejo

In Spanish, nouns have grammatical gender, and articles and adjectives must agree with them where needed.

In Spanish, adjectives usually come after the noun.

So:

• un espejo enorme = a huge mirror

Putting the adjective before the noun is sometimes possible, but it often sounds more literary, emotional, or stylistically marked. The most natural neutral order here is espejo enorme.

Also, enorme does not change form for masculine/feminine singular:

• un espejo enorme
• una mesa enorme

Para + infinitive is a very common way to express purpose in Spanish.

So:

• para reflejar más luz = in order to reflect more light

This structure is used when the purpose can be expressed without a new conjugated subject.

Examples:

• Estudio para aprender. = I study in order to learn.
• Abrí la ventana para ventilar la habitación. = I opened the window to air out the room.

Because para is used for purpose, goal, or intended result.

Here, the mirror was hung for the purpose of reflecting more light.

• para reflejar más luz = to reflect more light

Using por here would sound wrong because por usually expresses things like:

• cause
• reason
• exchange
• movement through
• duration

So for intention or purpose, para is the correct choice.

Because after para, Spanish commonly uses the infinitive when expressing purpose.

• para reflejar más luz
• literally: for reflecting more light
• naturally: to reflect more light

A conjugated verb would usually require a different structure, such as para que + subjunctive, especially if there is a different subject:

• Colgué un espejo para reflejar más luz.

  • same general subject/purpose structure

• Colgué un espejo para que la habitación pareciera más luminosa.

  • so that the room would seem brighter

Because luz here is being used as an uncountable noun in a general sense: more light.

In Spanish, as in English, mass nouns often appear without an article in this kind of structure.

• más luz = more light
• más agua = more water
• más tiempo = more time

You would only use an article if you were talking about a specific light in a specific context, which is not the case here.

Because en means in or inside, and the sentence is describing where the extra light is reflected.

• en el cuarto = in the room

Al cuarto would usually suggest movement to the room, which is not the idea here.

So:

• reflejar más luz en el cuarto = reflect more light in the room
• not movement toward the room, but light within that space

They are very similar, but not always identical in tone or usage.

• cuarto often means room
• habitación also means room, and can sound a bit more neutral or formal

In everyday Spanish, especially in many contexts, both can work:

• en el cuarto
• en la habitación

Depending on region and context, cuarto may sometimes sound especially natural for a bedroom or a room in a house, while habitación can feel a bit broader or slightly more formal. In this sentence, cuarto sounds perfectly natural.

Yes. While colgar literally means to hang, in natural English this sentence might often be translated as I put up a huge mirror.

That is because in context, hang a mirror and put up a mirror can refer to the same action. Spanish uses colgar when the object is suspended or mounted by hanging.

So:

• colgué un espejo = I hung a mirror
• often naturally translated as I put up a mirror

Yes. Grammatically, reflejar means to reflect, and the idea is that the mirror was hung so that it would reflect more light.

Even though the sentence does not explicitly repeat the mirror, that is the understood meaning:

• I hung a huge mirror to reflect more light in the room

Spanish often leaves this kind of relationship implicit when it is clear from context.

Yes, but it would change the structure.

With para + infinitive, the sentence is compact and natural:

• para reflejar más luz

With para que, you need a conjugated verb in the subjunctive:

• Colgué un espejo enorme para que reflejara más luz en el cuarto.

That version is also possible, but it is a bit heavier. In this sentence, para + infinitive is simpler and more idiomatic.

Yes. Enorme means huge / enormous, while grande usually means big / large.

So:

• un espejo grande = a big mirror
• un espejo enorme = a huge mirror

Using enorme emphasizes that the mirror is especially large, which helps explain why it would reflect more light.