coal可数吗?(煤)

　　I put more coal on the fire.

　　我往火里再加了些煤。

　　Demand for coal is down and so are prices

　　煤的需求下降了，煤价也相应下跌。

　　A hot coal fell out of the fire and burnt the carpet.

　　一块燃烧着的煤块从火炉里掉出来把地毯烧了。

　　It is important to get the coals white-hot before you start cooking.

　　很重要的一点是要把煤块烧到白热状再开始做饭。

　　Red-hot coals glowed in the fire.

　　炽热的煤炭在炉子里发光。

　　Taking a gun to the United States would be like taking coals to Newcastle.

　　带把枪去美国简直是多此一举。