题目内容
阅读下面短文,从每小题所给的A、B、C、D四个选项中选出最佳选项,并在答题卡上将该项涂黑。
The ice sheets covering the Arctic seas have thinned noticeably over the last seven years, most likely due to global warming. Melting polar ice means a rise in global sea levels, which translates into likely disaster for many coastal cities.
Boerge Ousland, a Norwegian explorer, made the alarming discovery while skiing alone across the top of the world in the winter of 2001.The extremely tiring trip lasted 82 days and took Ousland 1, 300 miles along the northern tip of Russia to the North Pole and down through Canada.
Along the way, the 38-year-old explorer measured the ice thickness as part of an ongoing study by the Norwegian Polar Institute. He compared his latest results to a similar voyage back in 1994.In some areas, he noticed that the ice had thinned by as much as a meter.
Ousland said he noticed other changes in the Arctic since his last visit, including a greater number of polar bears closer to the North Pole. One explanation could be that the bears need to travel further to hunt seals. The seals in turn have been driven from their own environments because of the thinning ice along the Pole's edges.
Ousland also reported seeing large pieces of driftwood from Siberia very close to the Pole. This is yet another sign that the ice is much thinner than usual.
The thinning ice also sets a more direct danger to Arctic explorers. Just before Ousland set out on his trip, a Japanese Polar explorer, Hyoichi Kohno, drowned after falling through the thin ice at one point less than a mile from where Ousland was.
1.Global warming is the cause that ________.
[ ]
A.makes the ice sheets cover the Arctic
B.melts the ice so that the sea level rises
C.causes danger to the world cities
D.has no connection with the tinning of the Polar ice
2.The average for the Arctic ice to melt is about ________ per year.
[ ]
A.more than l0 centimeters
B.less than 10 centimeters
C.as much as 1 meter
D.as much as 8 meters
3.From the passage we may know the fact that ________.
[ ]
A.there used to be a lot of polar bears close to the North Pole
B.the seals were driven to travel further north by the polar bears
C.driftwood was seldom seen so near the Pole in the past
D.the thinning ice along the Pole's edges carried the wood to Siberia
4.What is not true according to the passage?
[ ]
A.Boerge Ousland took the trip because he liked skiing.
B.Boerge Ousland works for the Norwegian Polar Institute.
C.Thinning ice makes it more dangerous for Arctic explorers.
D.If Hyoichi Kohno had traveled a mile away from his route, he wouldn't have died.