1.   Water appeared on the planet, __________ was fundamental to the development of life.

2.  In__________ (tradition) Chinese culture, marriage decisions were often made by parents for their children.

3.  One of Hawking`s__________ (theory) is so difficult that we can`t understand it.

4. She looked__________(puzzle) so I repeated the question.

5.   The photo will remind me__________ the days when we were together.

6.   He managed__________(go) to Shandong University by working hard.

7.   Practising Chinese kung fu can not only build up one`s __________(strong), but also develop one`s character.

8.   Passengers __________(permit) to carry only one piece of hand luggage onto the plane.

9.   __________is known that Canada is a large country with a small population.

10.   Vancouver is a beautiful city, ________(surround) by mountains and the Pacific Ocean.