题干
- What __________ Ben and Tony _________on Sunday?
- They are having a computer class.
A：is; doing
B：will; doing
C：are; doing
答案(点此获取答案解析）
C
- What __________ Ben and Tony _________on Sunday?
- They are having a computer class.
A：is; doing
B：will; doing
C：are; doing
则
的等差中项为（ ）
，其中
表示不超过
的最大整数，如
，若
有三个不同的根，则实数
的取值范围是
