The scene in the Hollywood movie The Day After Tomorrow, where global warming could soon turn the global climate (气候) into a new ice age, may never occur, according to new research.
The next ice age could be 15,000 years away, say European scientists who last month announced a continuous record of 7.40,000 years of climate data (数据) obtained from the Antarctic ice.                         
Scientists from 10 nations have now almost completely drilled through a 3,000-meter.depth of ice high in the Antarctic mainland. They figure out that the area where summer temperatures can fall to –40℃, has at least 900,000 years of snowfalls,, kept as neatly as the growth rings of a tree. And the ice and air caught in each layer(层) have begun to answer questions about the climates in the past..
The results show that there have been eight ice ages in the past 740, 000 years and eight warmer periods. And by comparing the pattern of global conditions today with those of the past, the researchers reported in Nature that the present warm period could last another 15, 000 years.
Research suggests that there is a very close connection between greenhouse gas levels and global average temperatures. It also shows that carbon dioxide (二氧化碳) levels are the highest for at least 440,000 years.         
"If people say to you: the greenhouse effect is a good thing because we would go into an ice age otherwise, our data say no, a new ice age is not hanging over our heads,” said Eric Wolff from the British Antarctic Survey. "Now we have eight examples of how the climate goes in and out of ice ages… and you can learn what the rules are that go into the climate models that tell us about the future."
Scientists found that whenever temperatures rose in the frozen record, so did carbon dioxide level. "In 440,000 years we have never seen greenhouse gas get as thick as it is today," said Dr Wolff.
48. In drilling through the ice in Antarctica, scientists, have found that______.
A. the lowest temperature there is －40℃     B. the depth of ice is 3,000 meters
C. the ice has existed for 15,000 years          D. snowfalls are kept in certain patterns
49. The information of the global climate conditions in the past can be obtained through______.
A. separating carbon dioxide from the air     
B. examining the growth rings of trees
C. comparing temperatures in different areas
D. studying the ice and air caught in each layer
50. We can infer from Eric Wolff's words that_______.
A. there is something wrong with the data     B. greenhouse effect is always a bad thing
C. a new ice age will not come in the near future
D. greenhouse gas will get thick in the future
51. What would be the best title for the passage?
A. Research over the Antarctic area.                    B. Warm period to last about 15, 000 years.
C. Report on the eight ice ages in the past.    D. Hollywood movies and the global climate.