在等高线地形图上，下列叙述正确的是（    ）

在等高线地形图上，下列叙述正确的是（    ）

    In the most southern part of our planet, there's a place that's covered with snow and ice all year round. But it has the clearest and cleanest air. Amazingly, in this place, the sun sometimes hangs even in the midnight sky. This place is Antarctica (南极洲): the coldest, windiest and harshest (恶劣的) place on the Earth.
    As the world's least-known place, Antarctica is of great interest to scientists around the world. In 1983, China joined the Antarctic Treaty (《南极条约》). The treaty made Antarctica a peaceful place for member countries to do scientific research. During 30 years, China has sent many scientists to Antarctica. They mostly look at the resources under the icy land and do research about climate change and marine (海洋的) biology.
Antarctica is a place with fantastic views. However, life there is very hard. Food is one of the biggest problems. Frozen food which can be heated easily is people’s daily food. Fresh vegetables are hard to grow in the cold weather. Therefore, scientists often eat dried or canned vegetables.
Sleep is also troublesome. In Antarctica, summer lasts from November to March. During this period, Antarctica points to the sun and receives sunlight 24 hours a day. In order to get some sleep, scientists cover the windows with black plastic cloth to create “night”.
    Working in Antarctica is dangerous, especially when meeting gale-force(七级以上的)winds.Sometimes the wind is even stronger than a typhoon.It can easily blow people away.So there are ropes that connect buildings of some research stations.People can hold these ropes to keep their balance in forceful winds.
    What's more, communicating with others is difficult. Without cables and Internet in some research stations, two-way radios are the only tools to communicate. If people want to say hello to friends and relatives, they can use satellite phones.
    Although it is challenging（挑战） to work in Antarctica, scientists' passion to learn about this mysterious land will never end. It is hopeful that one day they will step every corner of this icy land.