I borrowed a car and ran out of gas before I could get to the gas station. I still filled it up before I returned it though so it would not happen to her too.
That was a good idea. What do you think might have happened to her though?
I filled the gas up so she won't run out of gas while driving.
It is advisable and the polite thing to do to fill up a car before returning it. It's been done that way for ages.
Yes, that's part of why I did it.
Well it sounds like you did the right thing. I'm sure she won't mind lending it to you again in the future.