Holidaymakers who are bored with baking beaches and overheated hotel rooms head for a big igloo. Swedish businessman Nile Bergqvist is delighted with his new hotel, the world's first igloo hotel. Built in a small town in Lapland, it has been attracting lots of visitors, but soon the fun will be over. In two weeks' time Bergqvist's ice creation  will be nothing more than a pool of water. "We don't see it as a big problem," he says. "We just look forward to replacing it." Bergqvist built his first igloo in 1991 for an art exhibition. It was so successful that he designed the present one, which measures roughly 200 square meters. Six workmen spent more than eight weeks piling 1,000 tons of snow onto a wooden base; when the snow froze, the base was removed. "The only wooden thing we have left in the igloo is the front door," he says. After their stay, all visitors receive a survival certificate recording their success. With no windows, nowhere to hang clothes and temperatures below 0degC, it may seem more like a survival test than a relaxing  hotel break. "It's great fun," Bergqvist explains, "As well as a good start in survival training." The popularity of the igloo is beyond doubt: it is now attracting tourists from all over the world. At least 800 people have stayed at the igloo this season even though there are only 10 rooms. "You can get a lot of people in," explains Bergqvist. "The beds are three meters wide by two meters long, and can fit at least four at one time." According to the text, the first thing to do in building an igloo is   _  .
to gather a pool of water to prepare a wooden base to cover the ground with ice to pile a large amount of snow
Question: Holidaymakers who are bored with baking beaches and overheated hotel rooms head for a big igloo. Swedish businessman Nile Bergqvist is delighted with his new hotel, the world's first igloo hotel. Built in a small town in Lapland, it has been attracting lots of visitors, but soon the fun will be over. In two weeks' time Bergqvist's ice creation  will be nothing more than a pool of water. "We don't see it as a big problem," he says. "We just look forward to replacing it." Bergqvist built his first igloo in 1991 for an art exhibition. It was so successful that he designed the present one, which measures roughly 200 square meters. Six workmen spent more than eight weeks piling 1,000 tons of snow onto a wooden base; when the snow froze, the base was removed. "The only wooden thing we have left in the igloo is the front door," he says. After their stay, all visitors receive a survival certificate recording their success. With no windows, nowhere to hang clothes and temperatures below 0degC, it may seem more like a survival test than a relaxing  hotel break. "It's great fun," Bergqvist explains, "As well as a good start in survival training." The popularity of the igloo is beyond doubt: it is now attracting tourists from all over the world. At least 800 people have stayed at the igloo this season even though there are only 10 rooms. "You can get a lot of people in," explains Bergqvist. "The beds are three meters wide by two meters long, and can fit at least four at one time." According to the text, the first thing to do in building an igloo is   _  .
A. to gather a pool of water
B. to prepare a wooden base
C. to cover the ground with ice
D. to pile a large amount of snow
Answer: