阅读下面短文，把A-D四个句子填入文中空缺处,使短文内容完整正确，然后完成第80小题。 Chinese space lover Wang Yuan has been chosen as one of the volunteers for the Mars-500 test project. 小题1: Another five volunteers are all space. They are three Russians, an Italy-Colombian and a Frenchman. They will feel what it's like to travel to Mars without leaving the earth. During the whole process (过程), they are locked up for one and a half years under the condition which is similar to the red planet. So the experiment is called Mare-500. 小题2: Although the volunteers won't leave the building, they will feel as if(好像) they are on a real trip to Mars. The most difficult thing is that they will be separated from the people outside. 小题3: That will be hard. When reporters asked what they would miss most during the 500-day special life, Charles from France said, 'For me, it will be mainly my family, the sun and fresh air.' The main task is to study 'Man and Environment'. It will care about the astronauts' physical effects and the experience of staying there. 小题4: So they will have to make decisions by themselves and then report to the earth, and the earth will tell them whether they do the right thing or not. Each astronaut is preparing for the great challenge. And people are looking forward to the result of the experiment.