材料一统计资料表明，1952～1979年期间，我国按可比价格计算的社会总产值、工农业总产值和国民收入的年增长率，分别达到8.3%、8.3%、7.1%，这样的经济发展速度，高于世界平均水平。

材料二：同1949年相比，1978年国民收入中工业所占份额从12.6%上升到46.8%，农业所占份额由68.4%下降为35.4%，建筑业和运输业分别从0.3%、3.3%上升为4.1%、3.9%，并且具备了生产原子弹、氢弹的能力，国防力量大大增强。结合所学经济学常识的有关知识

下列函数为奇函数的是（　　）

    The Bamboo Train, or “Norry” in the local language, is quite famous in Cambodia. The train is in fact a big bamboo bed with four wheels and a small engine. It can run at the s____ of up to 50 km/h on the tracks. Lots of v____go to Cambodia to enjoy the Bamboo Train ride. They have to pay 5 dollars per person to g____on the train. The best time to take the train is from 4 to 6 o'clock in the afternoon, b____it is cool when people enjoy the countryside view. “It feels more like a roller coaster, but it's really nice,” a Germany tourist Theresa Kessemeier said after she c____a ride. The Bamboo Train has become a popular tourist at action.