Mi compañera me prestó la grapadora porque mi clip no sujetaba bien los folios.

Compañera is the feminine form of compañero. It can mean classmate, colleague, coworker, or sometimes just female companion, depending on context.

It is feminine because the person being referred to is female. If it were a man, you would say mi compañero.

So:

• mi compañera = my female classmate / colleague / coworker
• mi compañero = my male classmate / colleague / coworker

Me means to me.

The verb prestar means to lend, so:

• Mi compañera me prestó la grapadora = My classmate/coworker lent me the stapler

A very common mistake for English speakers is confusing lend and borrow. In Spanish:

• prestar = to lend
• tomar prestado or pedir prestado = to borrow

So this sentence means she gave the stapler to the speaker temporarily.

In Spanish, object pronouns like me, te, le, nos, os, les normally go before a conjugated verb.

So:

• me prestó
• te llamó
• nos dijo

That is just the normal word order.

With infinitives, gerunds, and affirmative commands, pronouns can attach to the end instead:

• va a prestarme
• está prestándome
• préstame

But in this sentence, prestó is a normal conjugated verb in the past, so me goes before it: me prestó.

This is one of the most important grammar points in the sentence.

• prestó is preterite
• sujetaba is imperfect

They are different because they describe different kinds of past actions.

prestó: completed action

Mi compañera me prestó la grapadora describes a single completed event: she lent it to me.

sujetaba: ongoing/background situation

mi clip no sujetaba bien los folios describes the situation or condition in the background: the clip wasn’t holding the papers well.

So the idea is:

• the clip was not holding the papers properly
• because of that, she lent me the stapler

If you said no sujetó bien, it would sound more like a specific one-time failure at a particular moment. No sujetaba bien sounds more like an ongoing problem.

Spanish often uses the definite article (el, la, los, las) when the object is already clear from context.

So la grapadora means the stapler. It is the stapler relevant in that situation, the one both people understand.

Why not su grapadora? Because the important point is not whose stapler it is, but simply that it was the stapler she lent. Spanish often avoids possessives when they are not necessary.

Why not una grapadora? Because una grapadora would mean a stapler, introducing it as a non-specific item. Here it sounds like a specific, known object.

Because porque means because, while por qué means why.

• porque = because
• por qué = why

So:

• Me ayudó porque tenía tiempo = He/She helped me because he/she had time
• ¿Por qué me ayudó? = Why did he/she help me?

In your sentence, it gives the reason, so porque is correct.

Yes, clip is commonly used in Spain to mean paper clip.

Its usual gender is masculine:

• el clip
• mi clip
• los clips

That is why the sentence says mi clip, not mi clips or anything feminine.

In some contexts, people may also use more descriptive words, but clip is very normal and natural in everyday Spanish in Spain.

Here sujetar means something like:

• to hold
• to keep in place
• to fasten
• to keep together

So mi clip no sujetaba bien los folios means the paper clip was not holding the sheets together properly.

This is a very good verb for situations where one object physically keeps another object in place.

It is not exactly the same as agarrar, which often means to grab or to hold with the hand.
Sujetar is better here because the clip is fastening the papers.

In Spain, folio often means a sheet of paper, especially in school or office contexts.

So:

• un folio = a sheet of paper
• los folios = the sheets / the papers

This is very common in Spain. In other Spanish-speaking countries, learners may hear hoja more often for sheet of paper.

In Spain:

• folios sounds very natural for paper sheets in everyday use
• hojas is also possible, but can sound a bit more general

So los folios here means the sheets of paper the clip was trying to hold together.

Because the two nouns are being presented differently.

mi clip

The speaker wants to identify that it was their own clip that was failing:

• my clip wasn’t holding the papers well

la grapadora

The stapler is just the relevant object in the situation:

• the stapler

Spanish uses possessives less often than English when ownership is obvious or unimportant. So la grapadora sounds natural even if it belongs to the coworker/classmate.

If you said su grapadora, that would emphasize that it was her stapler. That is possible, but the original sentence does not need that emphasis.

Usually, no—not automatically.

Compañera normally means someone you share a setting with, such as:

• a classmate
• a coworker
• a colleague
• a fellow student

It does not necessarily mean the person is your friend.

If you specifically want to say friend, the usual word is amiga.

So:

• mi compañera = my classmate/coworker/colleague
• mi amiga = my female friend

Yes, it matters.

• prestó = he/she lent or you (formal) lent
• presto = I lend or, in some contexts, an adjective/adverb in other uses

The accent mark shows the stress and helps identify the tense.

So:

• me prestó = he/she lent me
• presto would not mean the same thing in this sentence

For learners, this is a good reminder that written accents in Spanish are important, especially in verb forms.