A Variety of Stones各种各样的石头 There are a number of different kinds of building stone.Limestone is popular because it is hard,lasts a long time,and is easy to cut and shape.It is often placed over rough surfaces to make them more attractive.Marble is the most beautiful building stone.Unlike limestone,it is very colorful.It is not usually used in buildings because of its expense.Granite is even stronger and harder than limestone and is used most often for public buildings.However,it is hard to cut and handle.Like marble,granite can be polished to a shiny finish.Granite,limestone,and marble are just three of the many different building stones used today. ——文章来源网，仅供分享学习参考 ~ 1 ~ 本文来源：https://www.wddqw.com/doc/223f42e1bf1e650e52ea551810a6f524ccbfcb8f.html