31 st October —— A team of British explorers has announced t

31 ^st October —— A team of British explorers has announced they are going to the North Pole to measure the ice cap’s thickness. The exploration will take ground-based readings (仪表的读数) of an ice formation which most scientists agree is shrinking at an alarming rate.
Explorer Pen Hadow’s three-member team will pull a sled-fixed radar device, which measures ice density every eight centimeters, 2,000 kilometers across the Arctic and will produce millions of readings.
They will leave in February, 2008 and will face temperatures of -50℃ on a journey that will take up to 120 days. They have been testing their equipment in Britain and Canada.
Hadow is excited about the prospects (前景), “For the first time we will be able to transmit video images — webcam film of the expedition — as it unfolds so people can track us, and the whole idea is to engage as many people as we can in what we’re doing.”
New fallen snow on top of the ice makes ground-based measurements more accurate than satellite data.
“It has been in the planning stage for a while,” said Hadow. “We spent the last two years developing impulse radar (冲击雷达), which normally is about 100 kilograms and hangs under an aircraft and so on. We’ve managed to get it down to about 4 kilograms. It’s the size of a briefcase and we are dragging it behind the sled as we go.”
　　　　The ice cap shrank enough in 2007 so that a pathway through the cap known as the Northwest Passage opened up during the melting of the Arctic summer.
Cambridge University’s Joao Rodrigues explains, “Thickness of the ice cap will determine how much solar radiation will be reflected and the heat exchange between the ocean and the atmosphere and it is thus a vital component (成分) of climate models.”
If warming trends continue, some experts predict that the Arctic Ocean could be ice-free during the summer within a few decades.
１ What would be the best title for the text?
A. Exploration to the North Pole.
B. Arctic ice cap shrinking.
C. Arctic ice survey announced.
D. Ground-based measurements of ice.
２. What is special about the exploration?
A. It will be broadcast live on the Internet.
B. Explorers will use a sled-fixed radar device.
C. Explorers will travel in extremely cold conditions.
D. Ground-based measurements are more accurate.
３. What is the purpose of the exploration?
A. To measure the ice cap’s thickness.
B. To study whether ice will disappear in the Arctic.
C. To make a film about the Arctic exploration.
D. To make people interested in what they are doing.
４. It can be inferred from the passage that ________.
A. ice in the Arctic will disappear in ten years
B. the exploration will last for half a year
C. Hadow spent two years developing a kind of radar, which is about 100 kilograms
D. if there is snow on ice, satellites can’t measure the ice thickness accurately enough
５. From the passage, we learn that ________.
A. the explorers will measure ice density every other centimeter
B. people will be able to follow the explorers and see what they are doing  
C. people could go through the Northwest Passage in the 2007 Arctic summer
D. the equipment that Hadow’s team use will be tested in the United States