College is _______ time when you can learn many new skills, including how to live and work with_______ people from different backgrounds.
—Excuse me! Could you move your bike? It’s ______the way. --Sorry. I’ll do it at once.
Though he thought math was very difficult, he never _______it ______.
—Mom, I wonder ________. —Baby, I think you should study harder.
_________ our earth less polluted, or we will lose our home.
—Can you lend me the novel ________ you talked about the other day? —Oh, you mean the novel from Liuliu. No problem!