滤线栅铅条高度与其间隔之比为（）
A.栅比
B.栅密度
C.铅容积
D.栅焦距
E.滤线因数
参考答案：A
解析：滤线栅铅条高度与其间隔之比为栅比。
—Is Bob still teaching?
—I’m afraid not. He is said the school as he has become a businessman.
A．that he has left
B．to leave
C．to have left
D．to be left
具平肝潜阳之功的药物是（）
A.石决明
B.牡蛎
C.磁石
D.代赭石
E.龙骨
