落臂试验阳性提示为：（）.
A.颈椎病
B.肩周炎
C.冈上肌腱炎
D.肩袖破裂
E.肱二头肌肌腱滑脱
参考答案：D
John: What's the boy wearing? Lily: [ ]
A. She is wearing blue pants.
B. He is wearing blue pants.
C. He is a boy.
D. He likes English.
样本4，1，2，1，2的方差是（）。
A．6
B．1.4
C．1.2
D．0.8
