暴风雨来临时，我们赶紧关上了窗户的百叶窗。

We quickly closed the window ___shutters when the storm approached.

调整快门速度可以控制光线进入相机的时间。

Adjusting the ___shutter speed controls how long light enters the camera.

由于经济衰退，这家工厂不得不永久关闭。

Due to the economic downturn, the factory had to ___shutter permanently.