The Chinese Antarctica expedition returned to Shanghai on March 20 following a month living on the ice. It was the first time Chinese scientists had visited the Amery Ice Shelf--the longest ice shelf in the world. The team collected ice samples and data on temperatures, which are necessary for research on global warming. So far, about 27 countries have visited Antarctica for scientific research. Although the living conditions are very hard, many scientists have to stay there for long periods of time. So, how do they manage their lives on the ice? Well, during the summer, the temperature in Antarctica reaches about-20degC. It falls to about-60degCin winter. So, even if there are 24 hours of sunshine, scientists must keep wearing all the correct clothes to protect them from the cold. These clothes include jeans, running shoes, jackets, long underwears, boots and woolen socks. Although highly technical clothing provides much protection against the extreme cold, scientists often need to go outside when there is an icy wind blowing and the temperature is-30degC. Natural protection such as facial hair can also help. "That's why many researchers wear a beard. It really does keep you warm,"says German explorer Arved Fuchs. Usually, the polar researchers have good meals. Some even have feasts on holidays like Christmas and New Year's Day. Vegetables are always welcome and usually finished the quickest. Life on the ice means living with other researchers in tight living space. Most people sleep in dorm style rooms. More remote field camps use separate tents. So, at least some researchers don't have to _ annoying snorers . But what do they do for fun in their spare time?  There are actually a lot of things they can do. They watch movies, read tons of books, listen to music, have saunas ,paint and ski. Some female researchers might even do some knitting. It is important for a polar researcher to be in good physical condition. They can be required to climb to heights of more than 3, 000 meters. And the Antarctic atmosphere has less oxygen than that of any other continent. Which of the following do you think is the most important one to a polar researcher?
Clothes. Meals. Tents. Health.