________ you are interested in astronomy, you can read the book.
Nuclear science should be developed to benefit the people ______ harm them.
—May I smoke here? —If you ________, choose a seat in the smoking section.
If you want to catch the first bus you’d better ________ for the bus station immediately.
Walking around, I found the city was full of people _________ for the New Year’s festival.
We are looking forward to _________ a chance to watch the opening ceremony of Shanghai World Expo.