关闭图标
log图标

www.toeflonline.cn

  • 使用手机注册
  • 使用邮箱注册
  • 手机号不能为空!

    验证码不能为空!

    用户名不能为空!

    密码不能为空!

  • 邮箱不能为空!

    验证码不能为空!

    用户名不能为空!

    密码不能为空!

已有账号? 登录到雷哥托福
关闭图标
log图标
  • 使用手机找回密码
  • 使用邮箱找回密码
  • 手机号不能为空!

    验证码不能为空!

    密码不能为空!

  • 邮箱不能为空!

    验证码不能为空!

    密码不能为空!

又想起来了
加入生词本

listen

英['lɪs(ə)n] 美['lɪsn]
vi. 听,倾听;听从,听信
n. 听,倾听

已添加
×

我要举报草莓小菇凉评论

用户头像
草莓小菇凉:说的非常好,十分有道理,棒棒棒!

06-08 15:44:55

请选择举报类型:

举报电话:400-6021-727    举报QQ:2095453331
×
logo图标
分享到雷哥托福

分享成功图标分享成功

邀请名师点评成功,管理员正在安排老师进行点评。

继续做题 返回首页
支付雷豆失败图标 雷豆余额不足 购买雷豆 返回
报告题目错误
请选择错误类型:
请描述一下这个错误:

取消

TPO 15 -Geologic Time Periods

试音图标
查看听力原文

Listen to part of a lecture in a geology class.

As geologists we examine layers of sediment on the Earth's surface to approximate the dates of past geologic time periods.Ah sediment as you know is material like sand gravel, fossil fragments that is transported by natural processes like wind, water flow or the movement of glaciers.

So sediment is transported and then deposited and it forms layers on the Earth's surface over time. We examine these layers to learn about different geologic time periods including when they began and ended.For example, from about 1.8 million years ago to around 11 thousand years ago was the Pleistocene epic. The Pleistocene epic was an ice age.

During this epic, sediment was made by the kind of erosion and weathering that happens when the climate is colder, and part of those sediments are fossils of plants and animals that lived at that time.The Holocene epic followed the Pleistocene epic when the Earth's climate warmed up around 11 thousand years ago. 

The Holocene epic is characterized by different sediments, ones that form when the climate is warmer. Because the climate changed, the types of plants and animals changed also. Holocene sediments contain remnants of more recent plants and animals, so it's pretty easy to diffe rentiate geologically between these two epics.

Now there is growing evidence that the presence of humans has altered the earth so much that a new epic of geologic history has began - the Anthropocene epic, a new human-influenced epic. This idea that we have entered a new Anthro-pocene epic was first proposed in 2002. The idea is that around the year 1800 CE the human population became large enough, around a billion people, that its activities started altering the environment. This was also the time of the industrial revolution, which brought a tremendous increase in the use of fossil fuels such coal. The exploitation of fossil fuels has brought planet wide developments: industrialization, construction, uh, mass transport. And these developments have caused major changes like additional erosion of the Earth's surface and deforestation. Also, things like the damming of rivers has caused increased sediment production, not to mention the addition of more carbon dioxide and methane in the atmosphere.

Naturally all these changes show up in recent sediments. And these sediments are quite different from pre year 1800 sediment layers.Interestingly there's some speculation that humans started having a major impact on Earth much earlier, about 8000 years ago. That's when agriculture was becoming widespread. Early farmers started clearing forests and livestock produced a lot of extra methane. But I want to stress this is just a hypothesis. The idea that early humans could have had such a major effect, well I'm just not sure we can compare it with the industrial age. Geologists in the far future will be able t o examine the sediment being laid down today, whereas right now we can say that yes, human impact on the Earth is clear.It'll be future researchers who have a better perspective and will be able to really draw a line between the Holocene and the Anthropocene epics.


Question 1
What is the lecture mainly about?
核心词汇提示文字

网友解析

  • 用户头像

    敌军还有5秒到达现场 发表于 2017-03-23 11:17:19

    (主旨题)选A

    教授开头说we examine these layers to learn about different geologic time periods including when they began and ended(我们通过测量层级来学不同的地质时间段包括它们的起始)。因此和A完全对应

    • (0)
    • |
    • 举报

题目讨论

    TPO 15-listen
    马上开始精听

    标题图标听力排行榜

    • 头像
      • TPO1
      • 笑同学
      • 得分:30分
      • 小图标初来乍到
    • 头像
      • TPO2
      • 得分:30分
      • 小图标初来乍到
    • 头像
      • TPO3
      • kristina6812
      • 得分:30分
      • 小图标初来乍到
    • 4 .alright 30分
    • 5 .cccoo 29分
    • 6 . 29分
    • 7 . 29分
    • 8 .2095453331 29分
    • 9 .chaoyang 29分
    • 10 . 29分
    • 11 . 27分
    • 12 . 27分
    • 13 .wendyhjw 27分
    • 14 .我是奥利奥 27分
    • 15 .你的小仙女. 27分
    • 16 . 27分
    • 17 .Oldlady 27分
    • 18 . 27分
    • 19 .Jacklyn 27分
    • 20 . 27分
    • 21 .小糖包 27分
    • 22 .怒考800分 27分
    • 23 .贝朵皮 27分
    • 24 .ricey 26分
    • 25 . 26分
    • 26 .DG 26分
    • 27 .abccccccc 26分
    • 28 .蓝莓大西瓜 26分
    • 29 . 26分
    • 30 .llll 26分
    • 31 . 26分
    • 32 .xietianyi 26分
    • 33 .LysaWei 26分
    • 34 .123456 26分
    • 35 .lkedx 26分
    • 36 .Lunawhite0413 26分
    • 37 .oUosgh 26分
    • 38 . 26分
    • 39 .麻辣小荔枝 26分
    • 40 .JasonFang 25分
    • 41 .lain 25分
    • 42 . 25分
    • 43 .Yoga 25分
    • 44 .UniSun 25分
    • 45 . 25分
    • 46 .性感考拉的专用树 25分
    • 47 .大神 25分
    • 48 . 25分
    • 49 .书含 25分
    • 50 .王炸 25分
    查看详情图片

    联系雷哥托福

    全国免费咨询热线:400-6021-727

    预约托福考试规划师