单项选择题
A.20°~60°B.40°~120°C.80°~160°D.120°~200°
A.20°~60°B.50°~100°C.60°~120°D.80°~160°
A.主轴颈与轴瓦B.连杆轴颈与轴瓦C.凸轮轴与轴套D.活塞和活塞环与汽缸壁