托福阅读模拟试题：海水盐度分析

 　　Question 41-50

　　If the salinity¹ of ocean waters is analyzed², it is found to vary only slightly from place to place. Nevertheless, some of these small changes are important. There are three basic processes that cause a change in oceanic salinity. One of these is the subtraction³ of water from the ocean by means of evaporation⁴ —— conversion⁶ of liquid water to water vapor⁵. In this manner, the salinity is increased, since the salts stay behind. If this is carried to the extreme, of course, white crystals of salt would be left behind.

　　The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted⁸ so that the salinity is decreased. This may occur in areas of high rainfall or in coastal⁹ regions where rivers flow into the ocean. Thus salinity may be increased by the subtraction of water by evaporation, or decreased by the addition of fresh water by precipitation or runoff.

　　Normally, in tropical regions where the sun is very strong, the ocean salinity is somewhat higher than it is in other parts of the world where there is not as much evaporation. Similarly, in coastal regions where rivers dilute⁷ the sea, salinity is somewhat lower than in other oceanic areas.

　　A third process by which salinity may be altered is associated with the formation and melting of sea ice. When seawater is frozen, the dissolved materials are left behind. In this manner, seawater directly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared. Of course, when this ice melts, it will tend to decrease the salinity of the surrounding water.

　　In the Weddell Sea, off Antarctica, the densest¹⁰ water in the oceans is formed as a result of this freezing process, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portions of the oceans of the world.

　　4l. What does the passage mainly discuss?

　　(A) The elements of salt

　　(B) The bodies of water of the world

　　(C) The many forms of ocean life

　　(D) The salinity of ocean water

　　42. The word "this" in line 5 refers to

　　(A) ocean

　　(B) evaporation

　　(C) salinity

　　(D) crystals

　　43. According to the passage, the ocean generally has more salt in(A) coastal areas

　　(B) tropical areas

　　(C) rainy areas

　　(D) turbulent areas

　　44. All of the following are processes that decrease salinity EXCEPT(A) evaporation

　　(B) precipitation

　　(C) runoff

　　(D) melting

　　45. Which of the following statements about the salinity of a body water can best beinferred from the passage?

　　(A) The temperature of the water is the most important factor.

　　(B) The speed with which water moves is directly related to the amount of salt.

　　(C) Ocean salinity has little effect on sea life.

　　(D) Various factors combine to cause variations in the salt content of water.

　　46. The word "altered" in line 16 is closest in meaning to(A) determined¹¹

　　(B) changed

　　(C) accumulated

　　(D) needed

　　47. The world "it" in line 18 refers to

　　(A) sea ice

　　(B) salinity

　　(C) seawater

　　(D) manner

　　48. Why does the author mention the Weddell Sea?

　　(A) To show that this body of water has salinity variations(B) To compare Antarctic waters with Arctic waters(C) To give an example of increased salinity due to freezing(D) To point out the location of deep waters49. Which of the following is NOT a result of the formation of ocean ice?

　　(A) The salt remains¹² in the water.

　　(B) The surrounding water sinks.

　　(C) Water salinity decreases.

　　(D) The water becomes denser¹³.

　　50. What can be inferred about the water near the bottom of oceans?

　　(A) It is relatively¹⁴ warm.

　　(B) Its salinity is relatively high.

　　(C) It does not move.

　　(D) It evaporates quickly.

 

1 salinity   

n.盐分；咸度；盐浓度；咸性

参考例句：

• In the sea water sampled the salinity is two parts per thousand.在取样的海水中，盐度为千分之二。
• In many sedimentary basins the salinity of the formation water increases with depth or compaction.在许多沉积盆地中，地层水的含盐量随深度或压实作用而增高。

2 analyzed   

v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
• The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程，因为对他来说，爱是个不可分析的迷。 来自《简明英汉词典》

3 subtraction   

n.减法，减去

参考例句：

• We do addition and subtraction in arithmetic.在算术里,我们作加减运算。
• They made a subtraction of 50 dollars from my salary.他们从我的薪水里扣除了五十美元。

4 evaporation   

n.蒸发，消失

参考例句：

• Be careful not to lose too much liquid by evaporation.小心不要因蒸发失去太多水分。
• Our bodies can sweat,thereby losing heat by evaporation.我们的身体能出汗，由此可以蒸发散热。

5 vapor   

n.蒸汽，雾气

参考例句：

• The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
• This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。

6 conversion   

n.转化，转换，转变

参考例句：

• He underwent quite a conversion.他彻底变了。
• Waste conversion is a part of the production process.废物处理是生产过程的一个组成部分。

7 dilute   

vt.稀释，冲淡；adj.稀释的，冲淡的

参考例句：

• The water will dilute the wine.水能使酒变淡。
• Zinc displaces the hydrogen of dilute acids.锌置换了稀酸中的氢。

8 diluted   

无力的，冲淡的

参考例句：

• The paint can be diluted with water to make a lighter shade. 这颜料可用水稀释以使色度淡一些。
• This pesticide is diluted with water and applied directly to the fields. 这种杀虫剂用水稀释后直接施用在田里。

9 coastal   

adj.海岸的，沿海的，沿岸的

参考例句：

• The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
• This country will fortify the coastal areas.该国将加强沿海地区的防御。

10 densest   

密集的( dense的最高级 )； 密度大的； 愚笨的； （信息量大得）难理解的

参考例句：

• Past Botoi some of the densest jungle forests on Anopopei grew virtually into the water. 过了坊远湾，岛上的莽莽丛林便几乎直长到水中。
• Earth is the densest of all of these remaining planets. 地球是所剩下行星中最致密的星球。

11 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

12 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

13 denser   

adj. 不易看透的, 密集的, 浓厚的, 愚钝的

参考例句：

• The denser population necessitates closer consolidation both for internal and external action. 住得日益稠密的居民，对内和对外都不得不更紧密地团结起来。 来自英汉非文学 - 家庭、私有制和国家的起源
• As Tito entered the neighbourhood of San Martino, he found the throng rather denser. 蒂托走近圣马丁教堂附近一带时，发现人群相当密集。

14 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。