数控编程机械原点是（）。
A、机床坐标系原点
B、工作坐标系原点
C、附加坐标系原点
D、加工程序原点
参考答案：A
对肝硬化诊断最有意义的检查项目是（）
A.碱性磷酸酶
B.白／球蛋白比值
C.甲胎蛋白
D.胆红素定量
E.丙氨酸氨基转移酶
— How was your visit to Tibet?
— _____. The scenery is amazing! [ ]
A. It was wonderful
B. It was hard to say
C. I didn't enjoy it
D. It was unpleasant
