Because there is no abrasion between the concave and convex , the nut is reusable .
因为凹面与凸面没有磨损，螺母可以重复使用。
A concave mirror creates an image from this light using a design pioneered in the 17th century , by sir isaac newton .
早在17世纪，艾萨克.牛顿就开创性的利用这个光，让凹透镜产生了一个图像。
The roof 's concave shape deflects the wind and redirects it around the stadium .
屋顶内凹的形状可以使经过的风转向，让其环绕球场而过。
We can imagine the water spinning regardless of whether the bucket is spinning , by picturing the height of the water and whether it forms a concave surface .
通过想象水的高度和其是否在表面形成凹面，我们可以推测无论木桶是否自转，水都为自转。
Most astronomical telescopes employ reflection to focus starlight . A concave mirror creates an image from this light using a design pioneered in the 17th century , by sir isaac newton .
