There are over 58,000 rocky objects in ______space, about 900 of which could fall down onto______ earth.
—I thought you wouldn’t mind.—Well, as a matter of fact I ____; but you should have asked me first.
The time is not far away____modern communications will become widespread in China’s vast countryside.
Hardly ___________the door when he rushed into the office out of breath.
We want such materials ________ can bear high temperature and pressure.
Space exploration has been made ______ with the development of modern science and technology.