To take samples that retain the larger structure of the sediment, a core sampler is used. 为了保持样品沉积物的层次结构，就要用空心铁管采样器。
But now hollow rubber tyres are fitted on to wheels and the air acts like a soft cushion to help smooth out the bumps in the road. 可是现在给轮子按上空心橡胶轮胎，然后打足气，空气起着柔软的缓冲器那样的作用，帮助清除在路上碰到的东西。
