For example, theater scenery used to consist of large painted backdrops raised and lowered by stagehands who would whistle to signal each other.

比如，过的布景由大型的彩绘背景幕组成，由舞台工作人员升降，他们会用吹口哨的方式互相传递信。

At the back of the stage in most theatres there's a " backdrop, " a large curtain.

大多数的舞台后方，有一个“背景幕”，即一块大幕布。

Harry's gaze wandered to the portrait that sometimes contained Phineas Nigellus Black, Sirius's great-great grandfather, but it was empty, showing nothing but a stretch of muddy backdrop.

哈利的目光徘尼亚斯? 奈杰勒斯的肖像框上--他是小天狼星的曾曾祖父。但是现像框里什么都没有，只有一个泥泞的背景幕。