We have some books. But we need________.
Earth is becoming more and more polluted. ______, people will move to Mars one day.
_______ of the furniture in the museum ______ from Ming and Qing Dynasty.
—Why do you speak in ___ a loud voice? —Because I want to make myself ___ clearly.
—TV and computer are so popular these days. —Yes, they can______ our eyes to the outside world.
______ to improve our environment?