Re: He looked at his watch. 15 minutes had passed.

Originally Posted by
alpacinoutd
He got life for killing his daughter. The first day in prison seemed surreal. He looked at his watch. Fifteen minutes had passed. Great. Fifteen minutes down, an eternity left.
Or: an eternity to go.
It's good.
We usually spell out single-word numbers (even the ones with an article in front of them, like a hundred), and sentences always begin with capital letters.
I'm not a teacher. I speak American English. I've tutored writing at the University of Southern Maine and have done a good deal of copy editing and writing, occasionally for publication.