题目

It is the first time that Chinese astronaut Wang Yue________as one of the volunteers for the Mars-500 test project .     A. has been selected   B. had been selected   C. has selected  D. selected  答案：A 解析: 略人体将 、 ，以及多余的  和  等排出的过程称为排泄．尿素、多余的水分和无机盐主要通过  泌尿系统排出的．