kaisya no mausu ga ugokanai node, douryou ni karimasita.

の links 会社 and マウス and shows a relationship between them. Here it means something like the company’s mouse or the mouse at work.

So:

• 会社のマウス = the company mouse / the mouse from the office

In Japanese, の is used very broadly, not just for ownership. It can show possession, belonging, category, or association.

マウス here is the katakana loanword for a computer mouse. Japanese often uses loanwords for modern technology.

If you used ねずみ, that would mean the animal mouse, not the computer device.

So in this sentence:

• マウス = computer mouse

が marks マウス as the subject of 動かない.

The part マウスが動かない means:

• the mouse does not move
• the mouse does not work

Since the mouse is the thing doing or not doing the action/state of moving/working, が is natural here.

If you used は, it would sound more like setting the mouse up as the topic, often with a contrastive nuance. が is the more straightforward choice in this sentence.

Yes, 動かない literally means does not move. But in Japanese, it is often used for machines, devices, software, and controls to mean:

• not working
• not functioning
• unresponsive

So for a computer mouse, 動かない naturally means something like:

• the mouse isn’t working
• the mouse won’t respond

This is a very common Japanese way to describe broken or unresponsive devices.

ので means because or since. It connects the reason to the result.

So:

• マウスが動かないので、同僚に借りました
• Because the mouse wasn’t working, I borrowed one from a colleague

Compared with から, ので often sounds a little softer, more explanatory, and slightly more formal.

Before ので, Japanese usually uses the plain form:

• 動かないので
• 動いたので
• 寒いので

That is normal even in polite speech.

The sentence ends politely with 借りました, so the overall sentence is polite. This mix is very common:

• plain form before connectors like ので
• polite form at the end of the sentence

You can say 動きませんので in some formal situations, but 動かないので is more standard and natural in everyday polite speech.

With 借りる, the person you borrow from is marked by に.

So:

• 同僚に借りました = borrowed it from a colleague

This is different from English, where from is used. In Japanese, に often marks the source person with verbs like 借りる, もらう, and 教わる in certain contexts.

The object is omitted because it is obvious from context. The speaker borrowed a mouse.

So the full idea is:

• 会社のマウスが動かないので、同僚にマウスを借りました

But Japanese often leaves out words that are already understood. Since マウス was just mentioned, repeating it is unnecessary.

The sentence describes:

• the reason: the mouse does not work / was not working
• the completed action: I borrowed one

Japanese does not always match English tense in exactly the same way. 動かない can describe the state as a general present-state fact at that time: it isn’t working.

Then 借りました is past because the borrowing already happened.

A natural English translation may use past in both parts, but Japanese does not need to mirror that exactly.

Japanese often omits the subject when it is clear from context. Here, the person who borrowed the mouse is naturally understood to be I.

So even without 私は, the sentence is understood as:

• I borrowed one from a colleague because the company mouse wasn’t working

This kind of omission is extremely common in Japanese.

These two verbs are easy to confuse:

• 借りる = to borrow
• 貸す = to lend

So:

• 同僚に借りました = I borrowed it from a colleague
• 同僚に貸しました = I lent it to a colleague

The sentence uses 借りました because the speaker received the mouse temporarily from the colleague.

By itself, 会社のマウス most naturally means the office mouse or the company mouse, meaning a mouse associated with the workplace.

It usually suggests:

• a mouse belonging to the company
• a mouse used at the office

If the speaker wanted to clearly say my mouse at work, they might say something more specific depending on the situation, such as wording that includes 私の.

So this phrase most naturally points to a mouse connected with the company, not specifically a personal mouse.