函数y= $\frac{\sqrt{x-1}}{x+1}$ 的自变量取值范围是____．

中医常采用“切脉”来诊断疾病，切脉时触摸到搏动的结构是（　　）

给下列句子选择恰当的答语。⑴Where is classroom 4？ ____    A．It's next to the art room.
⑵This is my school.____           B．Yes，it is.
⑶Is this the teachers' office?____  C．It's so beautiful!
⑷Do you have a library?____      D．Yes，we do.
⑸Where is the gym?____          E．Classroom 4 is under the art room.

绘制某所中学的平面地图，其图幅大小与所选用的比例尺是相对应的，规律是（    ）

在一个圆中，圆的周长是直径的____倍，是半径的____倍。