stone可数还是不可数

例句：

The stone steps were worn and broken.

这些石头台阶被磨平破裂了。

The stone struck her on the forehead.

石头击中她的额头。

A large stone landed right beside him.

一大块石头正好落在他身旁。

Most of the houses are built of stone.

这些房子多数是用石头建造的。