单选题 Ocean water plays an indispensable role in supporting life. The great ocean basins hold about 300 million cubic miles of water. From this vast amount; about 80,000 cubic miles of water are sucking into the atmosphere each year by evaporation and returned by precipitation and drainage to the ocean. More than 24,000 cubic miles of rain descend annually upon the continents. This vast amount is required to replenish the lakes and streams, springs and water tables on which all flora and fauna are dependent. Thus, the hydrosphere permits organism existence.
The hydrosphere has strange characteristics because water has properties unlike those of any other liquid. One anomaly is that water upon freezing expands by about 9 percent, whereas most liquids contract on cooling. For this reason, ice floats on water bodies instead of sinking to the bottom. If the ice sank, the hydrosphere would soon be frozen solidly, except for a thin layer of surface melt water during the summer season. Thus, all aquatic life would be destroyed and the interchange of warm and cold currents, which moderates climate, would be notably absent.
Another outstanding characteristic of water is that it has a heat capacity which is the highest of all liquids and solids except ammonia. This characteristic enables the oceans to absorb ard store vast quantities of heat, thereby often preventing climatic extremes. In addition, water dissolves more substances than any other liquid. It is this characteristic which helps make oceans a great storehouse for minerals which have been washed down from the continents. In several areas of the world these minerals are being commercially exploited. Solar evaporation of salt is widely practiced, potash is extracted from the Dead Sea, and Magnesium is produced from seawater along the American Gulf Coast.
单选题 A characteristic of water NOT mentioned in this passage is that water ______.
  • A. expands on freezing
  • B. is a great solvent
  • C. is like ammonia
  • D. has a very high heat capacity
【正确答案】 C
【答案解析】文章并不是说Water is like ammonia，而是说它的沸点比除了ammonia的其他任何液体和固体都高。因此选项C不是水的特征，第2、3段分别叙述了水膨胀、高溶解力和高沸点等特性。
单选题 From this passage, we may conclude that ______.
  • A. ocean and land masses are equal
  • B. ocean masses are smaller than land masses
  • C. it is difficuit to get fresh water from the ocean
  • D. none of the above is correct
【正确答案】 C
【答案解析】本文并未对ocean mass与land mass进行比较，因此选项A、B不正确。最后—段讲到oceans a great storehouse for minerals which have been washed down from the continents(大海成厂一个储存从大陆上冲刷下来的诸多矿物质的仓库)，由此可以推断从海水中提取淡水可能会比较困难。所以答案为选项C。
单选题 By "hydrosphere" the author means ______.
  • A. the moisture in the air
  • B. the part of the earth covered by water
  • C. the Milky Way
  • D. the frozen waters of the earth
【正确答案】 B
【答案解析】本题可以采用排除法。文章开始就提到了海洋水的蒸发、降水循环以及海陆循环，是整个水圈，而非仅大气中的水，可排除选项A。选项C“银河”、选项 D“地球上的冻结水”，更不正确。B项是指地球上被水覆盖的地方，比较全面。
单选题 Fish can survive in the oceans because ______.
  • A. there are currents in the ocean
  • B. ice floats
  • C. evaporation and condensation create a water cycle
  • D. water absorbs heat
【正确答案】 C
【答案解析】第1段讲到大洋水的一部分蒸发到大气当中，又通过降水回到海洋，还有一部分降到大陆上，来补充生物赖以生存的河流、湖泊，因此Hydrosphere permits organic existence，可以看出生物能够生存是由于水蒸发和凝结作用形成的水循环。
单选题 "Anomaly", as used in the second paragraph, means ______.
  • A. state of being anonymous
  • B. abonormality
  • C. characteristic
  • D. property
【正确答案】 B
【答案解析】作者先提到，water has properties that unlike those of any other liquid(水的特性与其他任何一种液体都不同)，下文则紧接着以one anomaly为例说明水在结冰时体积变大，而其他液体都缩小，可以推断anomaly指abnormality。