He____2 hours ____ ____ his homework every day.
被誉为“夏宫”的建筑被焚毁于( )
两包饼干一共有____千克.
大包饼干比小包饼干多____千克.
某型号汽车发动机的额定功率为60KW,在水平路面上行驶时受到的阻力是2000N,求:
当人们忙于工作的时候,时间过的很快。
When people are busy with their work,____ ____ ____.