In four strokes engine, the cycle of events is completed in four strokes of ().
A. the cylinder
B. the crankshaft
C. the piston
D. the cross-head
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雷诺考特所具有的平衡脂/水溶性与其什么特性密切相关?()
A. 高效抗炎
B. 持久抗炎
C. 快速抗炎
D. 全部都对
采煤回风流净化水幕距工作面回风口10-50米回风巷内。()
A. 正确
B. 错误