那幅画挂在一个角度上，所以我把它摆正了。

The picture was hanging ___at ___an ___angle, so I straightened it.

我需要将设备倾斜到一个角度才能让它工作。

I needed to tilt the unit ___at ___an ___angle for it to work.

梯子以一个角度靠在墙上。

The ladder was leaning ___on ___an ___angle against the wall.