s climate. “This forcing is unusually effective，causing twice as much global warming as a carbon-dioxide forcing of the same magnitude，”Hansen noted．
6 Hansen cautioned．although the role of soot in altering global climate is substantial，it does not alter the fact that greenhouse gases are the primary cause of climate warming during the past century．Such gases are expected to be the largest climate forcing for the rest of this century． 7 The researchers found that observed warming in the Northern Hemisphere was 1arge in the winter and spring at middle and high latitudes．These observations were consistent with the researchers’ climate model simulations，which showed some of the largest warming effects occurred when there were heavy snow cover and sufficient sunlight． 1.Paragraph 3____________ 2.Paragraph 4____________ 3.Paragraph 6____________ 4.Paragraph 7____________
A Soots Role in Changes in the Climate and the Atmosphere B Observations of Warming in the Northern Hemisphere C Explanation of Increased Warming Effect Caused by Soot D Effort to Reduce Snow Albedo
E Ways to Reduce Soot Emission
F Greenhouse Gases as the Main Factor of Global Warming 5. In the twentieth century, soot_________ . 6. Hansen cautioned that greenhouse gases_________ . 7. Black soot covered snow and ice_________ .
8. A soot forcing is unusually effective, which_________ . A produces much more global warming than a carbon-dioxide forcing of the same magnitude
B contributed to 25 percent of observed global warming C can produce greenhouse gases
D absorb more of suns energy and warmth than white background E still surpass soot in warming the worlds climate during the last century
F can be seen mostly in the Northern Hemisphere
Icy microbes
1.In ice that has sealed a salty Antarctic lake for more than 2,800 years, scientists have found frozen bacteria and algae that returned to life after thawing. The research may help in the search for life on Mars, which is thought to have subsurface lakes of ice.
2.A research team led by Peter Doran of the University of Illinois at Chicago drilled through more than 39 feet of ice to collect samples of bacteria and algae. When Doran’s team brought them back and warmed them up a bit, they sprang back to life.
3.Doran said the microbes have been age-dated at 2,800 years old, but even older microbes may live deeper in the ice sheet sealing the lake, and in the briny water below the ice. That deeper ice and the water itself will be cautiously sampled in a later expedition that will test techniques that may one day be used on Mars. Expedite
4.Called Lake Vida, the 4.5-square—kilometer body is one of a series of lakes located in the McMurdo Dry Valleys of Antarctica, some 2,200 kilometers due south of New Zealand. This lake has been known since the 1950s, but people ignored it because they thought it was just a big block of ice. While at the site for other research in the 1990s, Doran and his colleagues sent radar signals into the clear ice covering the lake and were surprised to find that 62 feet below there was a pool of liquid water that was about seven times more salty
than seawater.
5.That prompted the researchers to return in 1996 with equipment to drill a hole down to within a few feet of the water layer. At the bottom of this hole, researchers harvested specimens of algae and bacteria.
reap
6.The researchers will return in 2004 equipped with instruments that are sterilized. They will then drill through the full 62 feet of ice and sample some of the briny water from the lake for analysis. The water specimen will be cultured to see if it contains life. Specimens from the water are expected to be even older than the life forms extracted from the ice covering. 答案与题解 : 1. Paragraph 2 ___. 2. Paragraph 3 ___. 3. Paragraph 4 ___. 4. Paragraph 6 ___.
A. Significance of testing techniques for sampling microbes in the deep ice sheet
B. special features of lake Vida
C. later expedition on mars
D. 2004 revisit planned for collecting lake water specimen E. Antarctic frozen life sampled and revived
F. Accidental discovery of ice-sealed lake water Antarctica 5. Scientists ignored lake Vida because they thought that a lake of ice ___.
6. Scientists expect that the life, if found in deeper water below the ice sheet, ____.
7. What the scientists will do in 2004 ___.
8. The salt concentration in the liquid water of Lake Vida ___. A. is found to be a great deal higher than that of seawater B. was of little scientific value
C. may be older than that collected below 39 sheet of ice D. might have come from Mars
E. is to collect some briny lake water for analysis
F. may return to life sooner than microbes frozen in the surface ice.
Compact disks
1 If someone says to you your music CDs don't really hold any music on them, and they only have numbers recorded on them, you