roof的复数形式

第三人称单数：roofs；现在分词：roofing；过去式：roofed；过去分词：roofed。

例句：

We could see the stars through an opening in the roof.

我们从屋顶的小洞能看见星星。

The stone made a dent in the roof of the car.

石头把车顶砸了个坑。

The roof of the tunnel fell in.

隧道顶部塌了下来。