— How many __________ do you have?
— I have one marker.[ ]
A. marker
B. markers
答案:B
计算:(-8)2004·(-0.125)2003
架承式悬挂就是将牵引电动机完全固定在()上。
A、转向架;
B、弹簧;
C、牵引梁;
D、车轴