'a' or 'the'?

[marko87]

If i want to tell someone that i have changed the batteries in my mouse and mention the word 'mouse' for the first time should i use 'the' instead of 'a'? The indefinite articles should be used when we mention something for the first time but 'the' sounds better to me in this case.The problem is i`m not sure if it`s correct to say 'a mouse' or 'the mouse'.

I`ve just changed the batteries in a mouse.
I`ve just changed the batteries in the mouse.

Thanks for Your help.

[JMB1122]

"I've just changed the batteries in my mouse is best.

I just changed the batteries in the mouse is something I would say to another person that uses the same mouse (wife - coworker).

I've just changed the batteries in a mouse is something you may say if your job is changing the batteries in mice (if you worked for a company performing hardware support on computer equipment).

[Casiopea]

In addition, 'the' is used when both the speaker and listener know/are aware of the object being mentioned. For example, here's a phone conversation between two friends:

Max: Hey, Sam. How's it going?
Sam: Pretty good, Max.
Max: Are you busy or do you have time to talk?
Sam: I've time to talk. I'm just putting a battery in a/my mouse.

Now, if Sam used the phrase 'the mouse', "I'm just putting a battery in the mouse", Max might ask, "What mouse is that?" or Max might assume that 'the' refers to Sam's mouse. You see, 'the' is specific. The noun it modifies is known to both the speaker and the listener.