A.2/1和2/2 B.1/1、2/1和2/2 C.1/1和2/1 D.1/1和2/2
A.順、逆和逆 B.順、順和逆 C.順、順和順 D.逆、順、逆
A.50mpm B.80mpm C.70mpm D.60mpm