stone可數還是不可數

例句：

The stone steps were worn and broken.

這些石頭臺階被磨平破裂了。

The stone struck her on the forehead.

石頭擊中她的額頭。

A large stone landed right beside him.

一大塊石頭正好落在他身旁。

Most of the houses are built of stone.

這些房子多數是用石頭建造的。