四级冲刺练习阅读(40)

雕龙文库 分享 时间: 收藏本文

四级冲刺练习阅读(40)

  When we analyze the salt salinity of ocean waters, we find that it varies 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 subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.

  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

  

  When we analyze the salt salinity of ocean waters, we find that it varies 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 subtraction of water from the ocean by means of evaporation. In this manner, the salinity is increased, since the salt stays behind. If this is carried to the extreme, of course, white salt would be left behind; this, by the way, is how much of the table salt we use is actually obtained.

  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

  

信息流广告 网络推广 周易 易经 代理招生 二手车 网络营销 招生代理 旅游攻略 非物质文化遗产 查字典 精雕图 戏曲下载 抖音代运营 易学网 互联网资讯 成语 成语故事 诗词 工商注册 注册公司 抖音带货 云南旅游网 网络游戏 代理记账 短视频运营 在线题库 国学网 知识产权 抖音运营 雕龙客 雕塑 奇石 散文 自学教程 常用文书 河北生活网 好书推荐 游戏攻略 心理测试 石家庄人才网 考研真题 汉语知识 心理咨询 手游安卓版下载 兴趣爱好 网络知识 十大品牌排行榜 商标交易 单机游戏下载 短视频代运营 宝宝起名 范文网 电商设计 免费发布信息 服装服饰 律师咨询 搜救犬 Chat GPT中文版 经典范文 优质范文 工作总结 二手车估价 实用范文 爱采购代运营 古诗词 衡水人才网 石家庄点痣 养花 名酒回收 石家庄代理记账 女士发型 搜搜作文 石家庄人才网 铜雕 词典 围棋 chatGPT 读后感 玄机派 企业服务 法律咨询 chatGPT国内版 chatGPT官网 励志名言 河北代理记账公司 文玩 朋友圈文案 语料库 游戏推荐 男士发型 高考作文 PS修图 儿童文学 买车咨询 工作计划 礼品厂 舟舟培训 IT教程 手机游戏推荐排行榜 暖通,电采暖, 女性健康 苗木供应 主题模板 短视频培训 优秀个人博客 包装网 创业赚钱 养生 民间借贷律师 绿色软件 安卓手机游戏 手机软件下载 手机游戏下载 单机游戏大全 免费软件下载 网赚 手游下载 游戏盒子 职业培训 资格考试 成语大全 英语培训 艺术培训 少儿培训 苗木网 雕塑网 好玩的手机游戏推荐 汉语词典 中国机械网 美文欣赏 红楼梦 道德经 网站转让 鲜花 社区团购 社区电商