读材料，完成下列各题．材料_ 2014年12月12日，南水北调中线工程正式通水，缓解了沿线群众的生产生活用水困难．材料二“南水北调工程中线路线图”（图1）、“南水北调中线地形剖面示意图”（图2）和“我国南北方水土组合状况比较图”（图3）．
阅读短文，回答问题。
It's eight o'clock. The children go to school by car every day. But they are walking to school today. It's ten o'clock. Mrs. Green usually(通常) stays at home in the morning. But she is going to the shops this morning. It's nine o'clock. Mr. Green usually reads his newspaper at night(晚上). But he is reading an interesting(有趣的) book this evening.
古罗马法学家西塞罗曾经说：“环顾我们国家中的其他部分，你会发现一切都依照规则和法律的规定而运转。”这句话反映出当时罗马社会( )
贵州至云南是沪昆高铁建设难度最大、耗时最长的一段，其主要原因是（ ）
