题目

完型填空：根据短文内容，从A、B、C、D四个选项中选出一个能填入相应空格内的正确答案。 The 2010 Shanghai World Expo has been open for several months and there are large numbers of volunteers serving there.     Chen Chuan，a 19- year-old student at Fudan University, is usually fast asleep at 6 am. But over the May 1 holiday, he was rising early to eat breakfast and    1    answer questions like，“Where can I find the toilet?” Such is the life of a Shanghai World Expo volunteer. But Chen and his 72,000 colleagues(同事)aren't complaining如图，把一块含有45°角的直角三角板的两个顶点放在直尺的对边上．如果∠1=20°，那么∠2的度数是（ ）A．30° B．25° C．20° D．15°