她当时在梯子上，正在擦窗户。

She was up a ___ladder, cleaning the window.

我祖父昨天修理坏掉的灯泡时从梯子上摔了下来。

My grandfather fell down from the ___ladder yesterday while he was fixing the broken light bulbs.

我需要拿一个梯子来更换天花板上的灯泡。

I need to fetch a ___ladder to change the light bulb on the ceiling.