肘关节的功能位是（）
A.0°
B.30°
C.60°
D.90°
E.120°
参考答案：D
若复数z1=4+3i，z2=cosθ+isinθ，且z1•z2∈R，则tanθ=______．
_____ is your mother? She's forty． [ ]
A. How old
B. How
C. How age
D. What age
