读四幅等高线图，回答下面小题．

    Most cities and towns in China have night markets(市场). During the day, these streets are quiet. At night, they become crowded(拥挤的)and lively. Usually, people get there at three or four in the afternoon. By 6:00, the streets are like rivers of people. Night markets are fun places to shop. You can buy clothes, shoes, and many other things. If you think the price is too high, you can bargain with the seller. You can also buy nice food. When you are hungry, you can sit down for a meal. Smelly tofu is popular, but it really smells bad! The best thing is that everything in night markets is cheap!

在西气东输工程的实施中，你认为应如何在西部地区实现经济效益和生态效益双赢？

 如图是某大学研究小组研发的一种独特的复合材料﹣﹣“石墨纸”．其成分以石墨为主，薄如纸张，比钢还要硬10倍且轻巧，还可以回收利用．下列说法错误的是（　　）