英语听力：自然百科 已知的宇宙：外星生命 Alien_Contact-2

Are we alone ?And it ties into all the big questions: how do we get here ? where are we going ?Are we a part of a bigger picture? But for the longest time ,the question was taboo to science . Before the Mid-1990s ,it was considered somewhat embarassi

英语听力：自然百科 已知的宇宙：外星生命 Alien_Contact-1

For thousands of years, weve wondered if we are alone in the cosmos. Life, is it a one-time event, or its something that's occurred lots of times throughout the universe.? And at this very moment, new discoveries are bringing us closer to the answers

英语听力：自然百科 北极海冰融化 海象上岸

Extreme ice melting led to thousands of walruses making an unusual gathering on the barrier island in Alaska. Biologists with the U.S. geological survey say the situation can be very dangerous, because walruses are easily startled and can't stampede.

英语听力：自然百科 海洋生物大揭秘

The Census of Marine Life has released the most comprehensive inventory life in the ocean today. Its an unprecedented database of marine species living in 25 key ocean areas around the world. The findings published in the open access scientific journ

英语听力：自然百科 海龟拯救行动

Young loggerhead sea turtles routinely migrate thousands of miles. But these turtles are starting their migration a bit early while still in the egg. In a typical year, as many as half of all baby sea turtles may die. Sea birds swoop down and snatch

英语听力：自然百科 神秘百慕大 bermuda triangle—15

The experiment proves that a rogue wave could have theoretically sunk the S.S.Poet. But Graber has spent 20 years studying this oceanic phenomenon. He knows there is no evidence to suggest that rouge waves occur more often in the Triangle than any ot

英语听力：自然百科 神秘百慕大 bermuda triangle—14

Hurricanes may have helped build the myth. But writer John Quiza believes they cant explain all of the disappearances. Anything can disappear in foul weather, but for it qualify as a Triangle disappearance, it has to have the unexplainable quality to

英语听力：自然百科 神秘百慕大 bermuda triangle—12

They looked for anything that may help identify the plane in the murky depths. You can see that may be 2,3 meters in front of you, yet at back, tremendous bottom motion of the water, if you dont hang on to something, it will move you really quickly.

英语听力：自然百科 神秘百慕大 bermuda triangle—11

You don't have to move far up shore before the depths are tremendous and to be able to find an individual wreck in depths like that would be extremely difficult even with modern multibeam sonar technology, and certainly, incredibly difficult with a t

英语听力：自然百科 神秘百慕大 bermuda triangle—10

The couple use global-positioning coordinates to close in on the underwater wreck. We're about 3.6 miles away and its directly southeast from this location. A dark shape looms in the water. It's pretty close. It's easy to be fooled by clouds flying o

英语听力：自然百科 神秘百慕大 bermuda triangle—9

It's very hard to tell. We've just hit the water. It's very hard to tell what altitude we're at. We've crashed the airplane at 930 feet. It seems clear that flying into that methane caused enough confusion in the instruments and with Thomas and he en

英语听力：自然百科 神秘百慕大 bermuda triangle—13

I think the part that Lauras talked about that it has the year 48 on it, and the size of this plan and some other things, I think we may have found the DC3 that disappeared in 1948.That is my real hunch. And I really don't see many other options for

英语听力：自然百科 走进西藏 tibet—16

The full entourage of Tibetan monks make the most of the occasion,with music, prayers, and blessings. Hundreds of fresh prayer flags are prepared and added to the pole. The head lama's sacred scarf adds the final touch to the proceedings. But the sig

英语听力：自然百科 大迁徙 Great Migrations—11

It's a grim end to a short life, but many of the surviving calves will face a more terrifying death. In the Mara River, another migration is culminating. Crocodiles have memorized when and where the wildebeests will try to cross. They have gathered i

英语听力：自然百科 走进西藏 tibet—17

The word for burial in Tibetan means giving offerings to the birds, an act of generosity, in line with the concept of compassion for all beings. By doing good deeds, Buddhists believe that they can contribute to the process of enlightenment. So a sky

英语听力：自然百科 走进西藏 tibet—15

Like a giant hotplate. The plateau heats up in the spring and summer. The change in air pressure draws in warm moist air from the Indian Ocean in the south. Thanks to this, over a billion people from India to Burma benefit from the monsoon rain that

英语听力：自然百科 走进西藏 tibet—14

Out on the plateau,new-born chiru are vulnerable to predators, so their mothers must try to hide and protect them. The most recent problem faced by the chiru is the new Tibet-Qinghai railway, which cuts right through their traditional migration route

英语听力：自然百科 北极熊 冰上间谍 Spy_Bear—7

She leaves little behind. Males are still on the lookout for females. For her cub's safety, she heads back to the hills. But as spring continues, lengthening days bring sudden and dramatic change. The highest tides of the year combine with the rising

英语听力：自然百科 北极熊 冰上间谍 Spy_Bear—6

But again, a bear helps with the filming. Sealed with a kiss, the couples whirlwind romance will last three weeks. Out on the frozen sea, a young male has killed a seal. He caught it when it surfaced through a breathing hole in the ice. To film from

英语听力：自然百科 北极熊 冰上间谍 Spy_Bear—5

She's aware of his difficulties and uses her body as a shield. She must stay attentive if her cub is to survive in this harsh Arctic world. Realizing he's exhausted, she digs a hollow to rest him. In the dens like this, she suckles him six times a da