用于人群普查的骨密度测量法是（）
A.SPA
B.DPA
C.DEXA
D.QCT
E.超声波
参考答案：A
—Would you like to come to our food festival?
—____ [ ]
A. Yes, I would.
B. Of course not.
C. Yes, I'd love to!
D. No, I wouldn’t.
A．定滑轮
B．动滑轮
C．滑轮组
D．无法确定
