On the subway to work, I can open a book, but I can't get started.

I open my study materials every morning on the way to work, but when the next station is announced, I lose my place.

Scenes

When the subway doors close, I open my book. — I open my study materials every morning on the way to work, but when the next station is announced, I lose my place. I started today too, but it feels like I haven't really studied anything.
The less time I have, the more I try to fill it. — When I open difficult material first so I won't waste even one stop, every interruption sends me back to the beginning. All that remains is the broken rhythm, not the pages.
Your study units need to change when you're on the move. — On the subway, it's easier to keep your rhythm by reading one paragraph and keeping just one sentence, instead of trying to finish something long. The rhythm of travel is different from the rhythm of focus.
Today, leave just one line behind when you get off. — Before opening your materials, decide on the one line you want to leave behind today. Even if you don't finish reading, that line gives you a starting point for your next study session.
You can continue with the next page at home. — If you have one line left when you get off, your commute study isn't over. The next page is already chosen, so starting again feels less daunting.