There are over 58,000 rocky objects in _____ space, about 900 of which could fall down onto _____ earth.
The scientist does not study nature ________ it is useful to do so. He studies it because he takes pleasure in it.
There is no doubt that _________ a goal, one needs not only knowledge but also good personalities.
Lyn gave up the chance of going abroad, but he feels he _________ a right decision.
It was the deep love and encouragement of my teammates_________ helped me gain the greatest strength and meet the challenges in life.
What makes tomorrow’s successful citizens_________ the ability to cope with a changing world as well as the responsibility towards community.