英语听力:探索发现

They huddle and turn to face the threat, a giant short-faced bear. Faced by a wall of horns, the bear moves on to sniff out a less daunting meal. Occasional blizzards are another harsh reality of living in Beringia, but the drifting snow may at least

发表于:2019-01-23 / 阅读(185) / 评论(0) 分类 探索与发现2012年

Musk oxen and arctic hares are well-insulated against the cold as are the largest grazers of them all, the woolly mammoths. This herd is regrouping, ready for a long day feeding on the grasses beneath the snow. Mothers need to keep milk flowing for t

发表于:2019-01-23 / 阅读(166) / 评论(0) 分类 探索与发现2012年

But back then, they had serious competition from the giant short-faced bear. The short-faced bears bone chemistry reveals it was a carnivore and up to a ton, probably the largest meat-eating mammal that ever walked the earth. On its long legs, it ran

发表于:2019-01-23 / 阅读(169) / 评论(0) 分类 探索与发现2012年

For these baby animals, it was a race to grow up over the brief summer to be tough enough to face the winter. One young animal that died in its first winter was discovered in the permafrost of an Alaskan gold mine. Recreated here are the best-mummifi

发表于:2019-01-23 / 阅读(201) / 评论(0) 分类 探索与发现2012年

Arctic ground squirrels hibernate like other small mammals, but with a unique twist. They can lower their body temperature right down to almost minus 3 degrees centigrade. But thanks to a biochemical super-cooling process, they dont actually freeze.

发表于:2019-01-23 / 阅读(132) / 评论(0) 分类 探索与发现2012年

Small ears also help to minimize heat loss, the opposite effect of those huge heat-dispersing ears of their relatives, African elephants. Other Beringia animals have more than a fur coat to help them cope with cold. This skull belongs to the bizarre-

发表于:2019-01-23 / 阅读(154) / 评论(0) 分类 探索与发现2012年

At its maximum, the ice covered nearly six million square miles. And in places, it was up to two miles thick. The ice blanket was punctuated only by occasional islands of rock, the peaks of the very highest mountains. Though Beringia itself remained

发表于:2019-01-23 / 阅读(130) / 评论(0) 分类 探索与发现2012年

The fact that both horses and mammoths were here suggests these forests werent. It seems that, 14,000 years ago, Beringia was a huge expanse of open grassland. This unique habitat of cold, dry grasslands is known as mammoths steppe. But thats not how

发表于:2019-01-23 / 阅读(176) / 评论(0) 分类 探索与发现2012年

This is Alaska today, a wetland of forests, boggy tundra, lakes and rivers rivers that still churn out fresh clues to the Ice Age past. This is a brick-sized tooth, and it belong to a woolly mammoth. Its narrow ridges of enamel tell us more about how

发表于:2019-01-23 / 阅读(162) / 评论(0) 分类 探索与发现2012年

The answer lies in the effects of North Americas immense and fluctuating ice sheets. As they grew, they locked up so much water that the sea levels began to fall. The Bering Sea between Asia and North America began to drain away, leaving a bridge of

发表于:2019-01-23 / 阅读(149) / 评论(0) 分类 探索与发现2012年

Bears have long claws, but they get worn down by the daily grind, moving around and rooting for food. They are just not sharp enough to rip into the bisons hide. To solve this puzzle, we need to look to Africa. African buffalo are similar in size to

发表于:2019-01-23 / 阅读(141) / 评论(0) 分类 探索与发现2012年

In one remarkable discovery recreated here, the head and hide of a large carcass was exposed a unique opportunity for scientists to tap some Ice Age secrets. The remains were of an extinct steppe bison, a longer-horned relative of the North American

发表于:2019-01-23 / 阅读(141) / 评论(0) 分类 探索与发现2012年

Of all these creatures, the woolly mammoth is the undisputed symbol of the Ice Age. But what do we really know about how this giant lived. How did it use its massive spiral tusks? Modern-day elephants, the mammoths closest living relatives, may provi

发表于:2019-01-23 / 阅读(171) / 评论(0) 分类 探索与发现2012年

Away from the herd, the dominant male mammoth is distracted from his usual routine, today he has a more urgent priority than food, a younger challenger that wants to take his place. This ritual clash of tusks will decide the future for them both. The

发表于:2019-01-23 / 阅读(168) / 评论(0) 分类 探索与发现2012年

The Yukon and its neighbor, modern-day Alaska, were once part of the land that was Beringia. Stunning though this region is today is just a shadow of the world that was encountered by the First Americans. Underground, the soil is frozen solid, as it

发表于:2019-01-23 / 阅读(137) / 评论(0) 分类 探索与发现2012年

By searching for evidence that still survives today, we reconstruct the landscape and the wildlife of prehistoric North America. During the last Ice Age, massive glaciers covered half of North America. But to the far northwest, there was a land that

发表于:2019-01-23 / 阅读(151) / 评论(0) 分类 探索与发现2012年

21st century, North America, where people have reached even the remotest corners of the continent, and pushed back the boundaries of modern technology. But it isnt so long since humans first set foot here about 14,000 years ago. And back then, North

发表于:2019-01-23 / 阅读(220) / 评论(0) 分类 探索与发现2012年

On Good Friday 1014, the opposing forces faced each other at Clontarf, outside Dublin. There were two Irish armies, but both with their Viking allies. Of these Vikings it was said they carried arrows anointed and browned in the blood of dragons. The

发表于:2019-01-23 / 阅读(139) / 评论(0) 分类 探索与发现2012年

Brian did not see himself as a king among equals but as high king of all Ireland, and with a mighty army he set about trying to control the island. In the only statement of his that we know about, he describes himself as Imperator Scottorum, Emperor

发表于:2019-01-23 / 阅读(144) / 评论(0) 分类 探索与发现2012年

By the 11th century, the Vikings who had settled in Ireland, the Hiberno-Norse, had been here for over a century and a half. Theyd intermarried, become Christian and formed local alliances. Theyd founded thriving port cities like Waterford, Wexford,

发表于:2019-01-23 / 阅读(147) / 评论(0) 分类 探索与发现2012年
学英语单词
2-3 trees
acute alkalosis
al hinw mt.
alissonotum pauper
Amorites
anchored choice
anterior thyroid artery (or thyro-laryngeal artery)
Antunite
armeniacae semen
assignment of negotiable securities
battery terminal
benzo rehoduline red b
bilge shore
blowbangs
bourgs
brothers in arms
Buffaholic
call indicator board
cauda equina claudication
cell cycle nonspecific agent
change manual page
cinesite
city resident
clock-time scheduling
conciliary
curilloside
dauntlessness
dedentation
equivalent knots
essential self-adjoint operator
excretory tubule
heat of radioactivity
heating schedule
hemolysis time
heuristic algorithm
hiracano
horizontal coil vat
immunoassaying
inter-government
interferoscope
iron oxide pigment
Jalibah
KCBT
Kloedenellacea
lattice mast
liquid blending system
local call
lucasville
Mayer problem in calculus of variations
mean density of spike
megagon
metal spinning
multilayer mirror
n-formylsarcolysin
national-security
netheravon
neutron worth
new ball game
noonmeat
off budget entity
on-line /gb/ (adjective)
orbit revisit problem
Palomera
pausally
placekick
polar opposition
position balancing method
progestagen
Pythic
rebronze
refrigerating
reimbursement irrespective of percentage
remove the needle
scalare
Sedon, Khouèng
Sherwāla
Simonovo
sloppy journalism
steam-ships
stick in the muds
stopthief
straightaway stands
stress cracks
suffragist
summat
superorbital abort
sympathetic hyperfunction
temporary tabular display
the dmv
three misthread defense
tongue bleeding
toxicity of metal dust
twos complement
Uigurian
undergraduateship
unnoteworthiness
Washington, DC
wekker
westones
window of opportunity
xanthidylic acid
yorkist