如图是青藏地区略图，图中黑粗线表示山脉的分布，据图回答：

水是重要的自然资源，水资源不足，将严重影响人类生存．请结合下表回答：

（1）我国的人均水量约为2300m³•a^﹣1，居世界80几位，水资源紧缺程度为 ____

（2）为保护有限的水资源，在防止水污染和节约用水两方面，你有什么好的建议和举措，试举二例：

防止水污染方面 ____，节约用水方面 ____

（3）生活中将硬水转变为软水的方法是： ____

（2015·茂名）阅读下面文章，根据文章内容，从每小题所给出的A、 B、 C、 D四个选项中选出最佳答案.

Many rules govern drivers on American streets and highways. The most common ones are the speed limits(限制). The speed limits control how fast a car may go.

On streets in the city,  the speed limitis usually 25 or 35 miles per hour.On the highways between cities, the speedlimit is usually 55 miles per hour. When people drive faster than the speedlimit, a policeman can stop them. The policemen give them pieces of paper which people call traffic tickets. Traffic tickets tell the drivers how much money they must pay. When drivers receive too many tickets, they probably cannot drive for a while. 

The rush hour is when people are going to work or going home from work. At rush hour there are many cars on the streets and traffic moves very slowly. Nearly all American cities have rush hours. Drivers do not get tickets very often for speeding during the rush hours because they cannot drive fast.