美国小学英语教材6:第23课 卡尔·阿克利将丛林带到美国(4)

The first of these to be built was the muskrat group, which still stands as good as new. 第一个威斯康星皮毛动物标本是麝鼠，如今还依旧如新。 From Milwaukee, Akeley went to the Field Museum of Natural History in Chicago. 从密尔

经济学人267:梦想之地,哈佛商学院

Business education 商业教育 Field of dreams 梦想之地 Harvard Business School reinvents its MBA course 哈佛商学院改良其工商管理硕士 (MBA) 课程 YOUNG mums shopping in the Copley Mall in downtown Boston last month found themselve

英语听力：自然百科 地球力场 Earth's Force Field—2

Radiation causes damage at the most fundamental level. It mutates the blueprint of life, DNA. Earth's magnetosphere is our crucial defense. It's so fundamental to our evolution and continued existence that the race is on to understand why it's changi

英语听力：自然百科 地球力场 Earth's Force Field—18

Earth's magnetic field has reversed thousands of times since its formation 4.5 billion years ago. And scientists now believe that the next reversal is imminent. The race is on to predicting exactly when it will occur. In 2010, the European Space Agen

英语听力：自然百科 地球力场 Earth's Force Field—16

During its magnetic cycle, the Sun undergoes periodic changes in activity. Every 11 years, it enters solar maximum. This 11 years cycle of solar activity has peaks where theres lots of solar storms. And right now where the sun is taking a little napp

英语听力：自然百科 地球力场 Earth's Force Field—12

Six years later, they come to believe these light flashes are the results of high energy, heavy cosmic rays penetrating the spacecraft and the crew members' eyes. These/ protons or electrons, just very, very high energy, ripped / part of atoms, sprin

英语听力：自然百科 地球力场 Earth's Force Field—13

Glatsmire's model shows that the magnetic poles swap places spontaneously due to / complex processes within the core. We were used to the idea that a compass points somewhere near the North Pole and hence we can use it for navigation, but there are p

英语听力：自然百科 地球力场 Earth's Force Field—15

By analyzing thousands of lava samples, geophysicists discover/ that the Earth's magnetic field has reversed over 18,000 times in the last 20 million years. On either side of these reversals is a long period of dramatically reduced field strength. Du

英语听力：自然百科 地球力场 Earth's Force Field—17

We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. We drive them about 20 miles away to the North, and release them, and we track them as they try to fly back home. Hes up, OK. Holland wa

英语听力：自然百科 地球力场 Earth's Force Field—14

By analyzing different samples of lava, Herrero / Bervera has built up a picture of how the filed has changed since long before humans were around. They are actually the recorders of the Earth's magnetic field in hundreds of years, thousands of years

英语听力：自然百科 地球力场 Earth's Force Field—5

If we could flip a switch and just turn off the Earth's magnetic field, it will take about 15,000 years to disappear, based on the rate of decay of the field that we've seen over the last 150 years. It's currently decaying at a rate that would see an

英语听力：自然百科 地球力场 Earth's Force Field—3

In polar regions where the magnetic field is / weakest, auroras glow in the sky. These dazzling displays of colored lights form when solar particles slam into gases in our atmosphere causing them to glow. The stronger the solar wind, the more dramati

英语听力：自然百科 地球力场 Earth's Force Field—4

Scientists believe that the South Atlantic Anomaly, is a sign of a global decline in the magnetic field. Evidence of this comes from a surprising source. Dr. Mimi Hill uses pottery to uncover the secrets of earth's magnetic past. Ancient pots tell us

英语听力：自然百科 地球力场 Earth's Force Field—6

It's clear from the fact that the Martian crust is strongly magnetized, that there must have been a magnetic field on Mars in the past, that the only way we know to magnetize rocks is for them to form in the presence of magnetic field. Why did Mars l

英语听力：自然百科 地球力场 Earth's Force Field—7

The loss of the magnetic field has a catastrophic impact on the planet's evolution. Mars becomes the red planet we see today. If earths magnetic protection continues to fade, would it suffer the same fate? If it vanishes completely, the planet might

英语听力：自然百科 地球力场 Earth's Force Field—8

Easily confused by this idea, there has a big thawed iron inner core, so that I think it's just the bar magnet, just permanent magnet frozen in nad, and that's where causes all the magnetic field. But it's too hot inside the Earth, that can't happen

英语听力：自然百科 地球力场 Earth's Force Field—9

As the vast sphere reaches / maximum speed, something incredible happens. Huge lines of magnetism arc in and out of the model core. Well, we can't see the magnetic field coming out of the experiment, we can measure them, we can put many different mag

英语听力：自然百科 地球力场 Earth's Force Field—10

Larry Newitt from the Geological Survey of Canada charts the movement of the magnetic North Pole as it wanders the icy reaches of northern Canada. To determine where the magnetic pole / is, we can't rely on one single observation. What I try to do is

英语听力：自然百科 地球力场 Earth's Force Field—11

Blockson's computer model reveals that at the South Atlantic Anomaly, the magnetic field isn't just weaker than anywhere else on the planet. It's actually reversed polarity. There is a patch on the core in the South Atlantic where things are not poin

《孙子兵法》（精选）英文版

孙子曰：兵者，国之大事，死生之地，存亡之道，不可不察也。 Sun Tzu said: The art of war is of vital importance to the State. It is a matter of life and death, a road either to safety or to ruin. Hence it is a subject of inqu