客车在运行途中，关门车不得为（）。
A.机后第一辆车
B.机后第二辆车
C.列车中部车辆
D.列车最后一辆车
参考答案：D
Leonardo da Vinci (1452-1519) ____ birds kept in cages in order to have the pleasure of setting them free.
A．is said to be buying
B．is said to have bought
C．had said to buy
D．has sad to have bought
机体组不包括干式或湿式气缸套。
