美国科学60秒 SSS 2013-05-10
时间：2019-01-20 作者：英语课 分类：Scientific American(五)月
The Arctic wasn't always covered in ice. Samples of settlement layer beneath the frozen lake show this region used to be a lot warmer and made by out in the future. The works in the general science. * gain a Russian lake 100 kilometers north of the Arctic circle contains layers of settlement than backed to the lakes for a nation 3.6 million years ago. Now s settlement course have reviewed the back then. Summers reached about 15 to 16 degree celcius. A good 8 degrees warmer than modern Arctic summers. These warm temperatures will support the plants like TH lasted until about 2.2 million years ago. Using the settlement core as a detailed 1 historic climate change, scientists conceive how to forest of Arctic gradually became covered in the i snow. These changes help us to understand details about the development of v. In addition, the satellite comes from a window of time during the p epoch 2 when greenhouse gas levels were only slightly higher than the isle 3 today. Such sensitivity, the small c that outside changes hint at the warm Arctic future.
- He had made a detailed study of the terrain.他对地形作了缜密的研究。
- A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。
- The epoch of revolution creates great figures.革命时代造就伟大的人物。
- We're at the end of the historical epoch,and at the dawn of another.我们正处在一个历史时代的末期，另一个历史时代的开端。