I got home _____ they were having dinner.
—I’m leaving now.—______ you turn off the lights and the computer.
The population problem may be ______ one of the world today.
Don’t ______ so often. It’s bad for your health.
—Mum, when can I watch TV? —As soon as your homework ______.
—I hear Mr. Zhang has gone to Beijing for a meeting. —Really? Do you know when he ______?