[单项选择]Tom will go to the Great Wall as soon as he ______ to Beijing.
A. will come
B. comes
C. come

The Great Wall of China
Walls and wall building have played a very important role in Chinese culture. These people, from the dim mists of prehistory have been wail-conscious; from the Neolithic period when ramparts of pounded earth were used to the Communist Revolution, walls were an essential part of any village. Not only towns and villages; the houses and the temples within them were somehow walled, and the houses also had no windows overlooking the street, thus giving the feeling of wandering around a huge maze. The name for "city" in Chinese (cheng) means wall, and over these walled cities, villages, houses and temples presides the god of walls and mounts, whose duties were, and still are, to protect and be responsible for the welfare of the inhabitants. Thus a great and extremely laborious task such as constructing a wall, which was supposed to-run throughout the country, must not have seemed such an absurdity.
However, it is indeed a common
A. honoured the god of walls and mounts
B. was an absurdly laborious task
C. may have made sense within Chinese culture
D. made the country look like a huge maze