Food, gas and vegetables have been ________ by rail directly to the city ever since the highways

were blocked.[ ]

A. preferred  

B. transported

C. packed

D. rescued

游泳的人用手和脚向后划水，人就前进，下列说法正确的是[ ]

A．人是施力物体不是受力物体

B．水是施力物体同时也是受力物体

C．水是施力物体不是受力物体

D．人先给水一个推力，然后水也给人一个推力