单项选择题
A.1/2 B.1 C.1.6~1.7 D.2
A.扫、排气存在气阀重叠角 B.弯流扫气的缸套下部受热不均匀 C.直流扫气的换气质量最好 D.换气质量取决于扫气压力的高低
A.130°~150° B.100°~120° C.150°~180° D.110°~130°