英语听力：2012-01-18 从南极到北极 From Pole To Pole—1

A hundred years ago, there are one and a half billion people on earth. Now, over six billion crowd our fragile planet. But even so, there are still places barely touched by humanity. This series will take you to the last wildernesses and show you the

英语听力：2012-01-20 从南极到北极 From Pole To Pole—2

The penguins stay when all other creatures have fled because each guards a treasurea single egg rested on the top of its feet and kept warm beneath the downy bulge of its stomach. There is no food and no water for them. And they will not see the sun

麻省理工学院公开课：单变量微积分03：求导四则运算及三角函数导数

分集介绍：导数，商数，正弦和余弦 Derivatives.of.products.quotients.sine.cosine

麻省理工学院公开课：单变量微积分01：导数和变化率

分集介绍：导数，斜率，速度与变化率 Derivatives.slope.velocity.rate.of.change

英语游戏:愚蠢的香肠

[全屏观看] 点击右键- 另存为 可保存这个Flash影片 Silly Sausage是Nitrome于2011年5月28日发行的一款益智类游戏，它是以香肠在尽量不碰到其它损失生命物体的情况下吃光所有的钻石再到达终点为标

英语听力：2012-01-27 从南极到北极 From Pole To Pole—5

They are constantly on the move. New-born calves have to be up and running the day they are born. But the vast herds do not travel alone. Wolves. Packs of them, eight to ten strong, shadow the migration. And they are hungry. Its the newly born calves

英语听力：2012-01-22 从南极到北极 From Pole To Pole—3

But they are hungry and eager to reach their mother whos delayed feeding them on this special day. Now she lures them with the promise of milk, the only food the cubs have known since they were born, deaf and blind beneath the snow some two months ag

英语听力：2012-01-25 从南极到北极 From Pole To Pole—4

Day 10. And the mother has let her cubs a mile from the den. Its time to put them to the test. Theyve grown enormously in confidence, but they dont have their mothers sense of urgency. At last it seems that they are ready for their journey. And they

英语听力：2012-01-29 从南极到北极 From Pole To Pole—6

Midsummer on the tundra and the sun does not set. At these altitudes, the suns rays are glancing and not enough of their energy reaches the ground to enable trees to grow. Youll need to travel five hundred miles south from here before that is possibl

英语听力：2012-02-01 从南极到北极 From Pole To Pole—7

As we travel south, so the suns influence grows stronger. And at 50 degrees of latitude, a radical transformation begins. Summers here are long enough for broadleaf trees to replace conifers. Broadleaves are easier to eat and digest, so now animals c

英语听力：2012-02-05 从南极到北极 From Pole To Pole—9

The advance of the seasons brings constant change. As the suns influence diminishes in the north, so the deciduous forests of America begin to shut down, losing their leaves in preparation for the dark, cold months ahead. One season hands over to ano

英语听力：2012-02-08 从南极到北极 From Pole To Pole—10

The character of the forest changes as we descend, becoming ever darker and damper, favoring different kinds of animals and plants. Less than two percent of the sunlight reaches the floor. But even here there is extraordinary variety. In the Great Is

英语听力：2012-02-15 从南极到北极 From Pole To Pole—13

The sun beating down on tropical waters powers the weather systems of the globe. Moisture evaporates from the warming ocean and rises to create great storms. The winds generated out at sea sweep inland across the continents. As they travel across the

英语听力：2012-02-03 从南极到北极 From Pole To Pole—8

Deer are frequent casulties of the harsh winter. And these leopards are not above scavenging from a corpse. African leopards could never survive here. But the Russian cats have thick fur to shied them from the cold. There are only 40 Amur leopards le

英语听力：2012-02-24 从南极到北极 From Pole To Pole—17

Their secret is teamwork. Impala are their favourite prey. They start to hunt and the pack splits up. An aerial viewpoint gives a new insight into their strategy. As the dogs approach their prey, they peel off to take up separate positions around the

英语听力：2012-02-26 从南极到北极 From Pole To Pole—18

The dogs know their prey must come out or drown. Now its a waiting game. The rest of the pack are calling. Theyve made a kill in the forest and this is an invitation to join in the meal. The impala is in luck. A pack this size kills once a day and ev

英语听力：2012-02-17 从南极到北极 From Pole To Pole—14

All across southern Africa, all animals are journeying for the same reason. Buffalo join the great track. Nowhere else on Earth are so many animals on the move for the same urgent purpose. They are all heading for the swamps of the Okavango, a vast i

英语听力：2012-02-19 从南极到北极 From Pole To Pole—15

At the peak of the dry season in the Kalahari, water arrives in the Okavango. It fell as rain a thousand miles away in the highlands of Angola and has taken nearly five months to reach here. The water drives out insects from the parched ground which

HEALTH REPORT - New Heart Drug Shows Promise in African Amer

HEALTH REPORT - New Heart Drug Shows Promise in African Americans By Cynthia Kirk Broadcast: Wednesday, November 17, 2004 This is Bob Doughty with the VOA Special English Health Report. Heart failure

听播客学英语 139 多丽丝·莱辛

Today we go on a journey. It starts in Sweden over 100 years ago; and then moves to London; and finally moves to future worlds and other planets. But we start in Sweden. Alfred Nobel spent his life finding ways to blow things up. He was born in 1833