题目

（本小题满分10分） 已知集合,,, R． （Ⅰ）求，； （Ⅱ）如果，求a的取值范围． 答案：答案3、—Would you mind        out the litter when you go out?  —No,          ． A． taking, I wouldn’t                               B． to take, you’d better not C． taking, not at all                        D． to take, certainly not