一束光线垂直地射到平面镜上，经反射后，反射角是 [ ]
A.90°
B.0°
C.180°
D.45°
答案：B
—How far is your family from here?
—It's about ten _______ walk.[ ]
A. minute's
B. minute
C. minutes'
D. minutes
一个工作分析项目可以胜任（）个具体目标。
