雅思tpo听力真题 雅思和托福具体怎么准备

备考雅思，首先需要恢复英文本身的功力，然后针对雅思考试的特点，进行系统的专项强化。因此，切实有效的作法是把备考雅思分成两个阶段来完成：实力恢复期和考题强化期。
实力恢复期需要完成的功课
英文实力恢复期需要完成的工作包括以下方面：词汇问题：有针对性的词汇表
任何形式的英文测试，都离不开词汇的准备，雅思也不例外。雅思学员最头疼的事情有两个，一个是词汇量，另一个是听力。头疼词汇量的原因在于，四六级，托福，GRE都有词汇表，照着背就是了，而雅思考试既未规定词汇量，又未提供词汇表，让考生觉得摸不着边际，无从下手。在这种情况下，需要自备词汇。
为保证顺利通过雅思考试,考生应当有三个基本的词汇表：英文核心2000词词汇表、雅思听力场景分类高频词汇表、写作常用词汇表。

听力方面，这是个最需要平时积累的雅思考试项目，想要在听力上面拿到雅思高分成绩，突击是完全解决不了问题的。从词汇到语音，各种问题都是需要 大家在平时的积累过程当中才能得到解决的。大家不妨可以从看美剧开始，当然如果喜欢看英剧就更好了。从需要字幕到不看字幕，如果愿意参加字幕组那么帮助就 更大。在临近考试的时候突击一下针对雅思听力考试的方法，还是有事半功倍的效果。雅思的听力在语速和口音上都很适中，如果平时能够用心多听，问题不大。
阅读方面，很多考生都觉得雅思阅读是阻碍大家拿到雅思高分成绩的一大障碍。因为雅思阅读文章很不容易做。这里教大家一个最关键的窍门，就是抓定 位词，材料就是做剑4到剑7的真题。定位词对很多人来说都是一个新的概念，做阅读题的时候不只是埋头阅读，虽然一开始时间总是个问题，也许根据定位词，题 目倒是能大致做对，但总是来不及做完，但熟能生巧后做题速度就提高了许多。
写作方面，雅思写作没有什么捷径可走，多写多练可能是惟一的方法。想要在写作上面拿到雅思高分成绩，就必须要贴近英语写作思维，这一点对中国的考生来说是需要一定的时间来练习的，只有经常写，经常观摩一些高分的范文，才能真正找到感觉，写起来也就不费劲了。
口语方面，雅思口语是中国考生答得最差的一个考试科目，这和中国的英语教育习惯有很大的关系.想要在口语中拿到雅思高分成绩，就必须要做到敢 说，并且能说得好，说的有条理。花时间练习口语，特别是针对第二第三部分话题的回答思路和模式，好好练习的话是会很有效果的。面试时一定要避免紧张慌乱的 心境，尽量做到有条理有逻辑地答复。
雅思考试的高分成绩不是突击复习就可以得到的，大家必须花时间和心思准备，毕竟一分耕耘一分收获。

托福高分关键点1：词汇量要强
考新托福考试的第一个关键是：单词量一定要强。首先我们知道，新托福的单词比过去的老托福有明显增加的趋向。过去老托福阅读文章只有350字每篇，新托福增加到700字每篇，对词汇的考察仍然是重头戏，词汇占的比重应该是所有阅读题目的1/4左右，如果我们在单词这一关有一个很好的突破的话，对于考新托福是非常有帮助的，新托福阅读最低标准也要求我们有8千左右的词汇量，这样的词汇量对同学们在美国读大一的时候的学习很有帮助，同学们所看的一般的、泛泛的文章不会有阅读上的障碍。
托福高分关键点2：听力能力要强
第二个关键点对中国考生来说，听力一定要强，而且一定要超强才可以，目前我们的学生中已经有很多高分学员，我们也可以看到很多同学的高分心得，在这些同学的备考过程中，我们发现一个特点，几乎所有的高分同学，听力一定是非常的强的，为什么呢?因为新托福中现在有四科，其中有三科主要考察我们听力的能力，第一块就是我们的听力部分。
第二块，口语有6道题目，第一、第二题不考听力，剩下的都在考听力，口语考察的是什么呢?你的听说读的综合运用的能力，在美国大学或者研究机构实际场景中的英文交流能力。第三块在写作中也考听力，除了独立写作还有一篇综合写作，要求我们先读，再听，最后再根据听到和读到的内容去写一篇。因此，几乎现在我的学生打高分的都是听力特别特别的强，我也建议大家在备考的过程当中，额外多听一点东西，把听力基础打牢。
因为现在我们同学听力材料的得到比过去容易得多，各个网站上都有很多听力材料的下载，还可以去美国的一些大学的网站上去，有的甚至把教授录音的片断，讲课的片断都放上去，这对我们都是非常有利的，然后我们可以以收听VOA等广播节目。
VOA也有一些东西对我们备考也是非常有利的，还有其他的很多材料，比如我个人感觉到“探索”英文版对我们来说是非常有力的一个备考材料，因为很多的题材都比较像新托福，跟托福的听力和阅读都比较像，这也是比较好的，所以考生如果你的听力弱的话，我建议大家听力是不惜一切代价尽快提高，这样对我们考托福来说是非常有力的。
托福高分关键点3：记笔记的能力是托福考察的重点
第三个能力也是托福成功备考的关键之一。我们在教学过程当中和我们老师在积极参加新托福考试的过程中发现的一个重要秘密--新托福还特别侧重考察一个学生记笔记的能力。为什么这么说呢?因为听力一般听一段就5、6分钟过去了，听得过程中没有题目出现，说完这几分钟以后才给你题让你去答题，在听的过程当中要大量的记笔记，然后根据你的笔记再去回答问题的话，你会回答的非常专业，口语也是一样的，口语尤其考察你记笔记的能力，因为口语的3、4、5、6题，都需要记笔记。3、4、5、6题要求我们综合听力、阅读的内容去口头回答问题，即读听说综合在一起，无论对阅读材料还是听力材料都需要我们记笔记的能力非常非常强。包括在写作当中也是一样的，作文部分的综合写作，要求我们阅读一篇文章，听一篇文章然后再写，因此，如果笔记记得比较好的话，对写作是很有帮助的。所以我们发现，其实攻克新托福的关键在于听力要好，词汇量要大，再就是迅速提高自己记笔记的能力，做到这些，新托福的高分其实是有路可寻的。
现在有托福教师总结了一套方法，听力老师要求学生在考试的时候，首先把自己的草稿纸分成几大块，这个部分只记一个问题，这个问题又可以分几块去记，比如说这篇文章的主题下面一小点，两小点，三小点，每一点怎么去记，都很清楚，其实在实际听力和口语考试的时候记笔记会有一个 专门的模板，这对我们来说特别有用。并且在记笔记的时候还有很多的小窍门，比如有很多的符号表示某一个英文单词，比如说我们说一个箭头号，往上的箭头号表示事物发展比较好，往下就不是很好，一个叉就表示没戏了。如果我们记market这个单词就非常的费力气，如果写成MKT就非常非常简单了，有的单词可能只写一个字母，所以我建议大家在考试之前一定养成记笔记的好习惯，同时迅速养成一套适合自己的记笔记方法。同时，记笔记的能力对同学们出国读书也是很必要的。记笔记的能力不仅是考托福的一个非常重要的能力，也是在美国大学能够成功的生存下去的必备能力，为什么呢?因为多数的中国同学到美国去以后，前三个月都是一个艰苦的适应期，说不太多，写也写不明白，听教授讲还听不太懂，所以很多的中国学生就拿一个小录音笔，教授讲，他录，回去再听，很痛苦的三个月的适应期，我们有一个老师是教口语的老师，从美国柏克莱大学毕业，在读书的时候，他们一个班分成很多学习小组，比如4个人一个小组，第一个人负责记A教授的笔记，另外一个人负责记其他教授的笔记，这一个人是玩命的记，其他的人就是辅助的记，到期末考试之前，大家在一起把笔记凑在一起，然后把这些笔记再整理出一份，一人一份，这样不能打高分，但至少可以保证及格不会出问题，但是打高分还要额外的努力。
这就说明乐记笔记的能力对于在美国大学课堂的生存非常的关键，如果你现在就掌握好了这个能力，这对于我们在美国大学，无论你出国读研也好还是读本科也好，对你的成功也会很有帮助的，所以我个人感觉，新托福的第三个成功的关键就是如何把笔记记得更好一些。
托福高分关键点4：模考and TPO
第四个关键点就是考前一定要做模考，因为听说读写各个分项的提高大家只要有合理的规划就不会有问题。而考前的模考对托福高分是非常关键的，国内一些培训机构几乎把海外发行的权威的考试辅导教材全部都引进过来了，三角洲出版社的、朗文的、巴郎的教材，还有一些其他的出版社的教材全部都引进进来，我们可以利用这些书大量的做模考。
除了这个模考之外，大家可以上ETS的网站找一个产品，叫TPO，这个模考题大概*30几美金，这些题目对我们来说是特别宝贵的，为什么呢?ETS的托福模考题其实就是过去考过的真题，所以很多同学考完了以后，发现模考的分数和实际分数差不多，因为它跟实际的托福考试的难度是一模一样的。并且TPO是上机进行考试，这样就给广大参加考试的同学提供了上机操作和实战的机会。
小马过河为你解答！~

一、话题
托福官方指南中将托福听力对话部分分为两类：office hours与service encounters。office hours是美国课后与老师交流的时间，讲的基本是一些与学术或是课程有关的问题。而service encounters则是校园中日常起居有关的话题。
近期来说conversation的话题包含讨论论文/研究项目、图书馆相关问题、工作选课相关问题等。依据去年考试频次主要考察的是如下话题分类
作业考试类，比如TPO12-C1
资讯类，比如TPO5-C1
校园服务类，比如TPO33-C1
图书馆相关类，比如TPO27-C1、TPO7-C2
课堂内容讨论类，比如TPO31-C1
工作就业类，比如TPO6-C1、TPO11-C2
细化其内容，主要讲的包含：
1、询问作业
a) 澄清作业具体要求b) 作业具体要求,步骤,先后顺序等问题c) 学生对完成作业难易度的判断
2、询问课程
a) 学生咨询选课计划,选多少,选哪些,及如何满足某些课的特殊要求b) 教授对学生选课计划的担忧 c) 教授对学生选课的建议 d) 该课程最终得分情况
3、询问论文
a) 对话目的- 确定论题, 选定题目有困难b) 讨论论文得分及被教授指出优缺点c) 论文进度及教授的具体要求 d) 请求延期
4、询问考试
a) 关于考试建议,复习建议 b)分数讨论,过低如何补救c) 大小测验占总成绩比重(出勤率及课堂参与度) d) 成绩单出现的问题(出错/更改)
5、图书馆场景
a) 还书是否及时 overdue, duedate b) 是否罚款 fine, check out(付帐后离开) c) 借书时困难的解决 put an hold on the book(预约借书) d) 还书时发生误会等
二、词汇
托福听力词汇是基础，在上述场景和话题中，有些词汇是经常出现的，大家一定要熟悉这些词汇。(是从听上熟悉哦)
professor’s office hour 教授答疑时间
lecture hall 讲堂，讲演厅，报告厅
tutorial 个别指导
deadline 最后期限，截止时间
overdue 过期的
schedule 时间表，计划v. 安排，计划
time slot 时间空档
signature签字，签名
dissertation 论文
course 课程
option 选修科目
presentation (国外学生在课堂上所做的)演讲
field work 野外考察 实地考察
attendance 出勤， 上课
information 信息
exam schedule 考试时间表
term 学期
date 日期
book 预定
department 院系
invigilator 监考人员
sign up 注册
sheet 单子
bulletin board 公告板
draft 草稿
dean 系主任
review 复习
draw up 结论
manually 手工的
consult 咨询
register 注册
physiology 生理学
sophomore 大二学生
second year course 大二课程
first year student 新生
transfer 转系转专业
begin my first lecture 开始第一次课
introduce 介绍
complete 完全的
approach 方法途径
laws of physics and chemistry 物理化学定律
process of life 生命进程
vital force 关键力量
philosophical approach 哲学方法
scientific experimentation 科学实验
final exam 期末考试
midterm 期中考试
multiple choice question 多选题
essay question 问答题
comprehensive exam 综合测试
the subject 主题
review 复习
text book 教材
class note 课堂笔记
the final will count for 50% of your grade 期末考试占总成绩的50%
research project 调查项目
run into problems 遇到困难
school bulletin 学校公告栏
required writing course 必修写作课程
first year student 大一新生
third year stuent 大三学生
research paper 调查报告
sign up 注册
cover the entire process of writing a research paper 涵盖论文写作的全过程
selecting topic 选择性题目
final format 最终格式
presentation 课堂展示
hand in 提交
assignment 作业
final grade 最终分数
class meeting 班会
lecture 讲座，课程
different concept 不同的概念
hand in 提交
issue 发行
revision 复习
grade 分数
research paper 论文
due 截止日期
proposed topics 推荐的论文选题
make comment 评论
the most frequent problem 最常见的问题
broad 广泛的
preliminary outline 初步提纲
schedule 计划表
available 可利用的
appointment 预约，约会
final outline 最终提纲
no more than two pages long 不得多于2页
thesis statement 论文陈述
precise statement 精确的陈述
conclusion 总结
以上就是常考的托福听力对话话题和常常会涉及到的词汇，同学们备考的时候一定要注意增加精听练习，提升自己的听音辨音能力，同时在听的过程中学会记录笔记、熟悉出题点。

托福TPO作为大家托福备考的模考工具，它的题目对我们有很大的参考价值，为了帮助大家备考，下面我给大家带来托福TPO2Part2阅读原文及参考答案，望喜欢。

托福TPO2Part2阅读原文

The Origins Of Cetaceans

It should be obvious that cetaceans-whales, porpoises, and dolphins-are mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke1 and blowhole2 cannot disguise their affinities with land dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like. Extinct but already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.

Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans. In 1979, a team looking for fossils in northern Pakistan found what proved to be the oldest fossil whale. The fossil was officially named Pakicetus in honor of the country where the discovery was made. Pakicetus was found embedded in rocks formed from river deposits that were 52 million years old. The river that formed these deposits was actually not far from an ancient ocean known as the Tethys Sea.

The fossil consists of a complete skull of an archaeocyte, an extinct group of ancestors of modern cetaceans. Although limited to a skull, the Pakicetus fossil provides precious details on the origins of cetaceans. The skull is cetacean-like but its jawbones lack the enlarged space that is filled with fat or oil and used for receiving underwater sound in modern whales. Pakicetus probably detected sound through the ear opening as in land mammals. The skull also lacks a blowhole, another cetacean adaptation for diving. Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans. It has been suggested that Pakicetus fed on fish in shallow water and was not yet adapted for life in the open ocean. It probably bred and gave birth on land.

Another major discovery was made in Egypt in 1989. Several skeletons of another early whale, Basilosaurus, were found in sediments left by the Tethys Sea and now exposed in the Sahara desert. This whale lived around 40 million years ago, 12 million years after Pakicetus. Many incomplete skeletons were found but they included, for the first time in an archaeocyte, a complete hind leg that features a foot with three tiny toes. Such legs would have been far too *all to have supported the 50-foot-long Basilosaurus on land. Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.

An even more exciting find was reported in 1994, also from Pakistan. The now extinct whale Ambulocetus natans ("the walking whale that swam") lived in the Tethys Sea 49 million years ago. It lived around 3 million years after Pakicetus but 9 million before Basilosaurus. The fossil luckily includes a good portion of the hind legs. The legs were strong and ended in long feet very much like those of a modern pinniped. The legs were certainly functional both on land and at sea. The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans. The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing. The large hind legs were used for propulsion in water. On land, where it probably bred and gave birth, Ambulocetus may have moved around very much like a modern sea lion. It was undoubtedly a whale that linked life on land with life at sea

Fluke: the two parts that constitute the large triangular tail of a whale

1. "Blowhole: a hole in the top of the head used for breathing

Paragraph 1: It should be obvious that cetaceans-whales, porpoises, and dolphins-are mammals. They breathe through lungs, not through gills, and give birth to live young. Their streamlined bodies, the absence of hind legs, and the presence of a fluke3 and blowhole4 cannot disguise their affinities with land-dwelling mammals. However, unlike the cases of sea otters and pinnipeds (seals, sea lions, and walruses, whose limbs are functional both on land and at sea), it is not easy to envision what the first whales looked like. Extinct but, already fully marine cetaceans are known from the fossil record. How was the gap between a walking mammal and a swimming whale bridged? Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.

托福TPO2Part2阅读题目

Directions: Mark your answer by filling in the oval next to your choice.

1. In paragraph 1, what does the author say about the presence of a blowhole in cetaceans?

It clearly indicates that cetaceans are mammals.

It cannot conceal the fact that cetaceans are mammals.

It is the main difference between cetaceans and land-dwelling mammals.

It cannot yield clues about the origins of cetaceans.

2. Which of the following can be inferred from paragraph 1 about early sea otters?

It is not difficult to imagine what they looked like

There were great numbers of them.

They lived in the sea only.

They did not leave many fossil remains.

Paragraph 3: The fossil consists of a complete skull of an archaeocyte, an extinct group of ancestors of modern cetaceans. Although limited to a skull, the Pakicetus fossil provides precious details on the origins of cetaceans. The skull is cetacean-like but its jawbones lack the enlarged space that is filled with fat or oil and used for receiving underwater sound in modern whales. Pakicetus probably detected sound through the ear opening as in land mammals. The skull also lacks a blowhole, another cetacean adaptation for diving. Other features, however, show experts that Pakicetus is a transitional form between a group of extinct flesh-eating mammals, the mesonychids, and cetaceans. It has been suggested that Pakicetus fed on fish in shallow water and was not yet adapted for life in the open ocean. It probably bred and gave birth on land.

3. The word precious in the passage is closest in meaning to

Exact

Scarce

Valuable

Initial

4. Pakicetus and modern cetaceans have similar

Hearing structures

Adaptations for diving

Skull shapes

Breeding locations

5. The word it in the passage refers to

Pakicetus

Fish

Life

ocean

Paragraph 4: Another major discovery was made in Egypt in 1989. Several skeletons of another early whale, Basilosaurus, were found in sediments left by the Tethys Sea and now exposed in the Sahara desert. This whale lived around 40 million years ago, 12 million years after Pakicetus. Many incomplete skeletons were found but they included, for the first time in an archaeocyte, a complete hind leg that features a foot with three tiny toes. Such legs would have been far too *all to have supported the 50-foot-long Basilosaurus on land. Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.

6. The word exposed in the passage is closest in meaning to

Explained

Visible

Identified

Located

7. The hind leg of Basilosaurus was a significant find because it showed that Basilosaurus

Lived later than Ambulocetus natans

Lived at the same time as Pakicetus

Was able to swim well

Could not have walked on land

8. It can be inferred that Basilosaurus bred and gave birth in which of the following locations

On land

Both on land and at sea

In shallow water

In a marine environment

Paragraph 5: An even more exciting find was reported in 1994, also from Pakistan. The now extinct whale Ambulocetus natans ("the walking whale that swam") lived in the Tethys Sea 49 million years ago. It lived around 3 million years after Pakicetus but 9 million before Basilosaurus. The fossil luckily includes a good portion of the hind legs. The legs were strong and ended in long feet very much like those of a modern pinniped. The legs were certainly functional both on land and at sea. The whale retained a tail and lacked a fluke, the major means of locomotion in modern cetaceans. The structure of the backbone shows, however, that Ambulocetus swam like modern whales by moving the rear portion of its body up and down, even though a fluke was missing. The large hind legs were used for propulsion in water. On land, where it probably bred and gave birth, Ambulocetus may have moved around very much like a modern sea lion. It was undoubtedly a whale that linked life on land with life at sea

9. Why does the author use the word luckily in mentioning that the Ambulocetus natans fossil included hind legs?

Fossil legs of early whales are a rare find.

The legs provided important information about the evolution of cetaceans.

The discovery allowed scientists to reconstruct a complete skeleton of the whale.

Until that time, only the front legs of early whales had been discovered.

10. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage?

Incorrect choices change the meaning in important ways or leave out essential information.

Even though Ambulocetus swam by moving its body up and down, it did not have a backbone.

The backbone of Ambulocetus, which allowed it to swim, provides evidence of its missing fluke.

Although Ambulocetus had no fluke, its backbone structure shows that it swam like modern whales.

By moving the rear parts of their bodies up and down, modern whales swim in a different way from the way Ambulocetus swam.

11. The word propulsion in the passage is closest in meaning to

Staying afloat

Changing direction

Decreasing weight

Moving forward

Paragraph 1: Extinct but already fully marine cetaceans are known from the fossil record. ■How was the gap between a walking mammal and a swimming whale bridged? ■Missing until recently were fossils clearly intermediate, or transitional, between land mammals and cetaceans.■Very exciting discoveries have finally allowed scientists to reconstruct the most likely origins of cetaceans. ■In 1979, a team looking for fossils in northern Pakistan found what proved to be the oldest fossil whale.

12. Look at the four squares [■] that indicate where the following sentence can be added to the passage.

This is a question that has puzzled scientists for ages.

Where would the sentence best fit?

13-14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

This passage discusses fossils that help to explain the likely origins of cetaceans-whales, porpoises, and dolphins.

●

●

●

Answer Choices

1. Recent discoveries of fossils have helped to show the link between land mammals and cetaceans.

2. The discovery of Ambulocetus natans provided evidence for a whale that lived both on land and at sea.

3. The skeleton of Basilosaurus was found in what had been the Tethys Sea, an area rich in fossil evidence.

4. Pakicetus is the oldest fossil whale yet to be found.

5. Fossils thought to be transitional forms between walking mammals and swimming whales were found.

6. Ambulocetus' hind legs were used for propulsion in the water

托福TPO2Part2 阅读答案

参考答案：

1、2

2、1

3、3

4、3

5、1

6、2

7、4

8、4

9、2

10. 3

11. 4

12. 2

13-14. 1 2 5

托福TPO2Part2阅读原文翻译

沙漠已经占据了地球表面积约四分之一，而且最近几十年正以惊人的速度扩张。沙漠化是指类似沙漠的环境漫延到原本并非沙漠的区域。据估计，地球表面另外四分之一的地方正面临沙漠化威胁。

沙漠化主要通过以下过程实现：首先自然植被不断减少，随后风力和 雨水 加速了土壤的腐蚀。有的时候松散的土壤全部被风刮走，留下石质化的表层; 其它 情况下细小的沙粒可能会被吹走，而正常沙粒大小的砂子不断堆积，从而形成移动的沙丘或者沙脊。

即便是在保留了土壤表层的区域，植被减少也已成为土壤大量吸取地下水的能力下降的典型因素。雨水对松散土壤的冲击会把细小的粘土颗粒冲到土壤空隙中，封闭了土壤并降低土地表层水的渗透率。地表对水的吸收急剧减少，大量水资源流失，因此土壤的腐蚀率也随即增加。地表吸收水分的能力进一步弱化使得土壤越发干燥，导致植被的进一步流失，于是便形成了土壤沙漠化的恶性循环。

在一些地方，沙漠面积的扩大很大程度上归因于干燥的气候条件。在过去的几千年里，不断增加的温室效应使得一些地方干旱问题愈发严重。倘若空气污染带来的温室效应继续恶化，沙漠化进程会在未来数十年内加速实现。

然而，可以肯定的是，大部分地区沙漠化主要都是由于人类活动造成，而非自然条件导致。沙漠边缘的半干旱土地所处的生态平衡环境非常脆弱，环境压力持续增加，而这些半干旱区域适应环境压力的能力极其有限。人口数量的增加使得人们不断向土地施压，依其提供食物和燃料。在湿润的季节里，土地兴许能够应付这些压力。但是在干旱的季节里，在沙漠周边的土地上，存在着这样一个十分普遍的现象：人类对土地施加的压力远远超过了土地自身减压的能力，因此最终形成了沙漠。

导致沙漠化的主要因素有四个：过度 种植 ，过度放牧，过分砍伐，过度灌溉。由于人口密度增加，人们对粮食作物的种植已经扩展到日益干燥的区域进行。这些区域很有可能经常会发生干旱，所以农作物种植失败是很正常的事情。大多数农作物的种植需要事先移除天然植被，而农作物欠收后又会留下大面积荒地，非常容易被风力和雨水侵蚀。

在半干旱地区，草坪是主要的天然植被，家畜 饲养 是当地的一项主要经济活动。在一个地区过量饲养家畜会导致植被覆盖面积减少，土地被大量践踏和碾碎。通常，随之而来的就是土地硬化和加速侵蚀。

在很多国家木材是用来做饭和加热的最主要燃料。人口增加带来的压力促使人们大量砍伐木材，导致许多城市和乡村周围大面积树木和灌木减少。同时人们大量使用烘干的动物排泄物作为替代燃料同样对土壤不利，因为这些珍贵的土壤成分调节剂和植物营养资源将不会再回归至土壤当中。

造成土地沙漠化的最后一个主要人为因素在于人类过度灌溉导致土壤的盐碱化。灌溉多余的水渗透到地下水位。假如没有排水系统的存在，那么地下水位上升，把溶解的盐分带到土壤表面。水分蒸发后，盐分留在了表面，形成白色的地壳层，这一地壳层阻止了空气和水接触地底下的土壤。

沙漠化问题异常严重，这是因为有佷广阔的地区和数量庞大的人群都受到了沙漠化的影响，而且要想逆转沙漠化的进程甚至减缓沙漠化的速度都面临着巨大的困难。一旦土壤被侵蚀，需要再经过几百到上千年的时间才会产生新的土壤。那些大量土壤仍保存完好的地方，亟需一个严谨而有力的保护政策和植被覆盖计划来保护现有土地。

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