在混凝土屋顶上尤其突出，因为混凝土是一种活性建筑材料，高温时会产生膨胀并导致移动。

This is especially important on a concrete roof, since concrete is a live material which can dilatate with high temperature and create movements on the roof.

youdao

之后，她又切钢和铁、搅拌混凝土，运转的机器、移动的建筑材料，所有加重噪声在我们身边。

And later, the cutting of the iron and steel, the stirring of the concrete, the running of the machines, the moving of those construction material, all aggravate the noise around us.

youdao