A. “一关前、二关后、三摘风管、四提钩” B. “一关塞门、二摘风管、三提钩” C. “一关前、二关后、三排风、四提钩” D. “一关塞门、二提钩&rdquo
A. 机油压力过低 B. 机油压力过高 C. 气缸窜油 D. 曲轴箱机油增多
A. has B. have C. there is D. there are
A. 正确 B. 错误