问题 问答题

物理世界

人类拥有的水资源

        地球上海洋水、湖泊水、河流水、地下水、大气水和生物水等各种形态的水总储量约为1. 39×1018m3,地球表面约71%被水覆盖着,从宇宙飞船上看地球,它更像一个“水球”. 

        地球上的水总储量虽然很大,但大部分是海水,海水含盐很高,淡化海水的成本高,目前尚不能推广.陆地储水中也有咸水,淡水只约占全球储水量的2. 53%,其中大部分还分布在两极冰川、雪盖、高山冰川和永久冻土层中,难以利用,可利用的只约占其中的30. 4%,即1.07×1016m3.    

        我国水资源总量为2.8×1012 m3(居世界第六位),但人均水量只有2 300m3左右,约为世界人均水量的四分之一(居世界第八十九位),许多地区已出现因水资源短缺影响人民生活、制约经济发展的局面.    

问题:

我们应该采取什么办法保护水资源?

答案

节约用水,防治水污染,采取节水技术,植树造林等,

口语交际,情景问答题
阅读理解

The United States covers a large part of the North American continent. Its neighbors are Canada to the north and Mexico to the south. Although the United States is a big country, it is not the largest in the world. In 1964, its population was over 185,000,000.

When this land first became a nation, after winning its independence (独立) from England, it had thirteen states. Each of the states was represented(代表) on the American flag by a star. All these states were in the eastern part of the continent. As the nation grew toward the west, new states were added and new stars appeared on the flag. For a long time, there were 48 stars. In 1959, however, two more stars were added to the flag, representing the new states of Alaska and Hawaii.

Indians were the first people of the land which is now the United States. There are still

many thousands of Indians now living in all parts of the country. Sometimes it is said that the Indians are "the only real Americans". Most Americans come from all over the world. Those who came first in greatest numbers to make their homes on the eastern coast of North America were mostly from England. It is for that reason that the language of the United States is English and that its culture and customs are more like those of England than those of any other country in the world.

68. The United States didn't have______ states until _____.

A. thirteen; 1959      B. fifty; 1959  

C. fifty; this land first became a nation     D. fifty;1964

69. Why is English the language of America?

A. English is the Indian's native language.     

B. Most Americans come from all over the world.

C. Most of the people who first settled in America were from England

D. Canada is America's nearest neighbor.

70. Which of the following is the best title for the passage?

A. The States of America            B. The Language of America

C. The United States of America      D. The Culture and Customs of America