题目

We can never forget the days ______ the two astronauts in spaceship worked together and the days ______ we spent together. A . when; which B . which; when C . what; that D . on which; when 答案：A函数的自变量x的取值范围是（ ）A．x≥2B．x≥3C．x≠3D．x≥2且x≠3