飞机在重量一定的条件下,上升率主要取决于()。
A.飞机的速度
B.飞机的油门大小
C.剩余推力大小
D.剩余功率大小
参考答案:D
古罗马时期,由卸任行政长官任总督的省是( )
A.一级省B.二级省C.三级省D.四级省
Train services are usually ________ and run regularly every day. [ ]
A. reliable
B. reasonable
C. flexible
D. comfortable