阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）中选出最佳选项。

B

    In China, more and more middle school students are getting shorter sleeping time than before. Most students sleep less than nine hours every night, because they have much homework to do. Some homework is given by their teachers, and some by their parents. Also, some students don't know how to save time. They are not careful enough while they do their homework, so it takes them a lot of time. Some students spend too much time watching TV or playing computer games. They stay up（熬夜）very late. Some students have to get up early every morning on weekdays to go to school in time by bus or by bike. It may be a long way from home to school.

    Schools and parents should cut down some of the homework so that our children can enjoy more than nine hours of sleep every night for their health. For children, we should make best use of our time. When we have enough time for sleeping, we will find it much better for both our study and health.

阅读材料，完成下列问题。

材料：塔里木河流域是我国重要的棉花、石油化工基地，也是新疆的特色果品生产基地。“漫卷风沙埋河道，欲哭无泪哀胡杨”是塔里木河下游断流、干涸多年的真实写照。

塔里木河流域近期综合治理规划的做法是：上游，实施老灌区节水防渗改造，并在源流上建若干个山区水库；中游，修建堤防，以减少每年因决口而浪费的上亿立方米的河水；下游，跨流域调水。

音乐会上，一位女士姗姗来迟，刺耳的鞋跟声搅乱了听众的兴致。钢琴家灵机一动，现场为女士量身创作，响起的音乐随着她的步伐时快时慢，时轻时重……全场观众都被女士的“舞步”逗得哈哈大笑，该女士面红耳赤。这告诉我们（    ）