Six Americans are working on a new highway. But this highway won't have any traffic.It's an "ice highway" to the South Pole. The team has just finished a second year of work on the 1,020-mile highway. "The road is the greatest single footprint of activity we've seen in the Antarctic  ," said Alan Hemmings, an Australian environmentalist. The highway will provide a new way for supplies to be trekked (, ) across the earth on tractor-pulled sleds  . This method will use a lot less fuel than an aircraft, the current   way that scientists and supplies reach the Amundsen-Scott Base, a U.S. research station in the South Pole. The highway will also allow for equipment that is too big for planes to carry to be brought to Antarctica.Even with these benefits, there is one disadvantage--a round trip on the road will be 30 days, compared to a few hours by plane. Making this 20-foot-wide road isn't easy, and it takes a lot of time. The crew   has been working on the road for two summers, when it's warmer and easier to work with the ice. It probably won't be completed until 2006. Crevasses  , or cracks, in the land often make the construction difficult. Crevasses are kind of like pot holes that form when surface ice is stretched.This can be very dangerous, especially when the crevasses are hidden under a layer   of snow and can't be seen. "Last year it took us three months to go three miles across a crevasse field, full of dangerous, hidden crevasses," said the project's manager, John Wright. Each year, more crevasses appear and they have to be filled with snow and ice so the road is safe for travel. The road will also be lined with green flags so travelers know where the safe surface is. It will probably take   _   years to complete the ice highway.
2 4 6 8
Question: Six Americans are working on a new highway. But this highway won't have any traffic.It's an "ice highway" to the South Pole. The team has just finished a second year of work on the 1,020-mile highway. "The road is the greatest single footprint of activity we've seen in the Antarctic  ," said Alan Hemmings, an Australian environmentalist. The highway will provide a new way for supplies to be trekked (, ) across the earth on tractor-pulled sleds  . This method will use a lot less fuel than an aircraft, the current   way that scientists and supplies reach the Amundsen-Scott Base, a U.S. research station in the South Pole. The highway will also allow for equipment that is too big for planes to carry to be brought to Antarctica.Even with these benefits, there is one disadvantage--a round trip on the road will be 30 days, compared to a few hours by plane. Making this 20-foot-wide road isn't easy, and it takes a lot of time. The crew   has been working on the road for two summers, when it's warmer and easier to work with the ice. It probably won't be completed until 2006. Crevasses  , or cracks, in the land often make the construction difficult. Crevasses are kind of like pot holes that form when surface ice is stretched.This can be very dangerous, especially when the crevasses are hidden under a layer   of snow and can't be seen. "Last year it took us three months to go three miles across a crevasse field, full of dangerous, hidden crevasses," said the project's manager, John Wright. Each year, more crevasses appear and they have to be filled with snow and ice so the road is safe for travel. The road will also be lined with green flags so travelers know where the safe surface is. It will probably take   _   years to complete the ice highway.
A. 2
B. 4
C. 6
D. 8
Answer: