摘要
[问4] （1） It produces metals, precious stones, coal, grain, meat and wines, and has the biggest iron mines in the world. （2） Materials such as paper, glass or metal are collected, sorted, treated and used again.从句（1）来看，metal是个可数名词，而从句（2）来看，它是个不可数名词。它到底是个什么样的名词呢？（广东广州杨月娇）
