题目内容：

Each year 1.(thousand) of tourists visit the polar regions of the Arctic and Antarctica. But the increasing number of people traveling to the ends of the Earth can have2.negative effect on fragile ecosystems. Should tourists3.(allow) to visit polar regions?

About 40,000 tourists visit Antarctica each year. More than five million travel to the Arctic and sub-Arctic. Transporting tourists to the regions 4.(increase) ship and airplane traffic, adding to the risk of pollution, oil spills, and other 5.(environment) damage. Because the places where wildlife is accessible 6.(be) few in number, tourist traffic can become concentrated in specific areas, 7.(put)Arctic vegetation at risk.

Others say that access8. these very special parts of the world should not be restricted to only researchers and scientists. Polar tourism allows people to develop deep 9.（person） connections with polar regions. “Those 10. travel to the Arctic or Antarctica often become cheerleaders for supporting those places.” Jim Sano, vice president for travel and conservation at World Wildlife Fund, told TFK.