题目

       The human body is a living machine, and, like all machines, it needs fuel （燃料） to supply it with energy．This is provided by the food we eat．But how much do we need to stay healthy?        The energy value of food is usually measured in calories．A calorie is the amount of heat required to raise the temperature of 1 kg of water by 1℃．The number of calories people need per day is different．Also, the number of calories you use at any one moment normally depends on the activity you are in．For example, you need more calories for standing than for sitting, mor2012年9月29日21时16分，中国首个空间实验室“天宫一号”由长征二号FT1运载火箭在中国西北酒泉卫星发射中心升空。据此回答下列各题。1.从太空中瞭望地球，可以观察到( )A. 地球是个不规则球体B. 地球表面有无数条经线和纬线C. 地球上高大的建筑和公路上飞驰的车辆D. 地球的地轴和两极2.当太阳直射北回归线的时候，下列说法可信的是（ ）A. 香港比北京的白昼时间长B. 我国中小学生已经放寒假C. 北极地区有极夜现象D. 澳大利亚此时是冬季