—Mama, why can’t I work the math problem out?—Oh, let me see. Well, you a figure here. Got it?
This is the factory ________ we visited last Monday.
______ you have finished your work, you ought to have a good rest.
All of her time was devoted to_______ her homework, so she had no time to have fun.
When you sleep, your body prepares you for the day _______.
Last summer I took a course on _______ poisonous gases.