阅读下面四篇材料，然后从各题所给的四个选项中选出一个最佳答案．
(2015•义乌)
Real Tennis
An amazing chance
This summer at Grange Rood
Your chance to enjoy Real Tennis, the king of racket
tennic starts on 6th July with the World Champion(冠军)
6：30pm—8：00pm, 6July
A wonderful introductory (入门的) evening with Rob Fahey, the world champion from Australia and widely regarded as the greatest player ever. With an amazing exhibition match: The World Champion vs The British Amateur (业余的) Champion, David Woodman,
Plus…
Your turn to play
Professional (专业的) coaching during a two-hour group lesson to give you the basics any time you like this summer, with rackets and balls provided. It’s indoors, so there is no chance of being rained off !
A lasting gift
A copy of the fascinating book Real Tennis in Cambridge to help you understand the place of the game in our great city.www.21-cn-jy.com
Unexpected value
The introductory evening, the book, and the group lesson are just 50 pounds for each person. For further information or to book your place, please call Manuel Simpson ay 01223357141 or e-mail Jeff Green at mani@curtc. net
2C(g)，当平衡向正方向移动时，下列说法一定正确的是