There is thing as a free lunch.
— Have you finished your paper?— Not yet. It will be another two weeks _____ I can get it done.
People are paying more and more attention to the environment _____ they live.
Chang’e-3 made China become the third nation _____ an unmanned spacecraft on the moon.
— Could you do me a favor to take this book to John?— _____
By the time the storm ended, more than 200 people in that area _____.