A round manhole cover cannot fall t

A round manhole cover cannot fall through its circular opening, whereas a square manhole cover could fall in if it were inserted diagonally in the hole. Circular covers don't need to be rotated or precisely aligned when placing them on the opening. A round manhole cover is easily moved and rolled.

Results (Chinese) 1:

一圆形孔盖无法通过其圆形开口下降，而当其在孔斜着插入正方形孔盖可能会下降英寸 圆形盖不需要旋转或将在开幕的时候他们精确地对准。一个圆形井盖容易移动和滚动。

Results (Chinese) 2:

圆形人孔盖不能穿过其圆形开口，而方形人孔盖如果沿对角线插入孔中，则可能会掉落。将圆形盖放在开口上时，无需旋转或精确对齐。圆形检修孔盖易于移动和滚动。

Results (Chinese) 3:

圆形人孔盖不能通过其圆形开口落下，而方形人孔盖可以通过对角插入孔中落下。圆形盖放在开口上时不需要旋转或精确对齐。圆形井盖易于移动和滚动。