The opposite of evaporation is precipitation, such as rain, by which water is added to the ocean. Here the ocean is being diluted so that the salinity is decreased. This may occur in areas of high rainfall or in coastal 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.
Normally, in hot 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 dilute 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, the densest water in the ocean 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 portion of the oceans of the world.
26. This passage mainly tells us about_______.
A. the analysis of the salinity of ocean waters
B. the causes of the variation in oceanic salinity
C. the importance of the changes in oceanic salinity
D. the different forms of salts in ocean waters
27.It can be known from the passage that increase in the salinity of ocean water is caused
by______.
A. melting of sea ice B. precipitation
C. evaporation D. supplement of salt
28.Which of the following is not the cause of the decrease in the oceanic salinity?
A. Precipitation. B. Rain and snow.
C. Formation of ice. D. Addition of water by rivers.
29.Which of the following statements is TRUE according to the passage?
A. Oceanic salinity has great effect on sea life.
B. Many factors combine to cause changes in oceanic salinity.
C. The movement of the water is related to the amount of salt.
D. The temperature of the water has much to do with the oceanic salinity.
30.The purpose of mentioning the Weddell Sea is_______.
A. to give an example of cold-water salinity
B. to point out the location of deep waters
C. to make a comparison between hot-water salinity and cold-water salinity
D. to show that the water in the Weddell Sea varies in salinity from place to place
26. B 27. C 28. C 29. D 30. A
【复习方略】2017版高考英语一轮外研版课时提升作业:必修3 Module 1《Europe》(含解析)
2017届广东省惠阳县高考英语语法填空一轮选练:4(含答案)
2017届广东省惠阳县高考英语语法填空一轮选练:2(含答案)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修2 Module 4《Fine Arts-Western,Chinese and Pop Arts》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修4 Module 4《Great Scientists》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修5 Module 6《Animals in Danger》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修6 Module 4《Music》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修5 Module 3《Adventure in Literature and the Cinema》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修7 Modules 3、4(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修6 Module 1《Small Talk》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修5 Module 2《A Job Worth Doing》(含解析)
【创新方案】2017届高考英语一轮复习专题滚动检测:综合检测(含解析)
2017届(全国卷地区)高考英语一轮复习学生手册:必修3 Unit 5《Canada—“The True North”》听课手册
【复习方略】2017版高考英语一轮外研版课时提升作业:选修7 Modules 5、6(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修2 Module 5《Newspapers and Magazines》(含解析)
2017届广东省惠阳县高考英语语法填空一轮选练:5(含答案)
2017届广东省惠阳县高考英语语法填空一轮选练:3(含答案)
2017届广东省惠阳县高考英语语法填空一轮选练:1(含答案)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修1 Module 4《A Social Survey—My Neighbourhood》(含解析)
2017届广东省惠阳县高考英语语法填空一轮选练:7(含答案)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修6 Module 3《Friendship》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修6 Module 2《Fantasy Literature》(含解析)
2017届(全国卷地区)高考英语一轮复习学生手册:必修3 Unit 5《Canada—“The True North”》作业手册
【复习方略】2017版高考英语一轮外研版课时提升作业:选修8 Modules 5、6(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修4 Module 1《Life in the Future》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修5 Module 5《The Great Sports Personality》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修1 Module 5《A Lesson in a Lab》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:必修4 Module 5《A Trip Along the Three Gorges》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修6 Module 5《Cloning》(含解析)
【复习方略】2017版高考英语一轮外研版课时提升作业:选修6 Module 6《War and Peace》(含解析)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |