Of course, not all commodities are equal. For example, although the case for copper seems straightforward, given that it is a key input for wiring, electronics, and indoor plumbing, a strong bid for iron is not as obvious, given the Chinese infrastructure boom that already has occurred in the last two decades.
当然，并非所有商品都是如此。比如，铜需求量大增一眼就能看出——因为它是电线、电子元件和室内水管的重要投入品，而钢需求量大增就没有这么明显——因为中国的基础设施繁荣发生在过去二十年中。