over作为介词的用法
1、在……上方（垂直）；在……上面
There's a bridge over the river. 河上有座桥.
Spread a cloth over the table. 给桌子上铺块布.
A lamp hung over us. 我们头上吊着一盏灯.
The magistrate looked at the merchant from head to foot, and a faint smile passed over his face.
那个官员把商人从头到脚看了一遍，一丝淡淡的微笑掠过他的脸上。
You can't wear a blue jacket over that shirt—it'll look terrible.
你不能把一件蓝夹克穿在那件衬衫的外面，太难看了。
It was very difficult to build and rebuild such a great wall over wild and distant country without any modern machines.
没有现代 ...