阅读理解。 World Horticultural Expo 2011 (2011西安世界园艺博览会) The 2011 International Horticultural Exposition will be held in 'Xian from April 28th to October 22nd in the year 2011. Chang'an Tower, the highest building in the expo garden, serves as the symbol of Xi'an Expo. People can go up to the observation decks (观景台) at the top and catch the whole view of the expo grounds and the historic city. Theme Park is designed to be integrated with the surrounding dock (码头) and land terrains (地形). The Theme Pavilion is the main building that has been specially built  for the 2011 International Horticultural  Exposition. The Greenhouse is built mainly of glass and steel, and it is on Splendid Lake in the eastern side of the expo park. Guangyun Entrance is the main entrance to the Expo site. It's amazing because it crosses the 60-meter wide Expo Avenue and that it can hold as many as 20,000 passengers during peak hours (高峰时间). 1. _______, visitors can catch the whole view of the expo grounds and the historic city. A. On Changan Tower B. In the Theme Park C. In the Greenhouse D. At Guangyun Entrance 2. The Greenhouse is in the _______ side of the expo park. A. northern B. southern C. western D. eastern 3. Guangyun Entrance can hold about _______ passengers during peak hours. A. 40,000 B. 30,000 C. 20,000 D. 10,000