But when aluminum reacts with oxygen, it forms aluminum oxide, which is non-reactive and protects the pure metal underneath.

但是当铝与氧气反应时，它会形成氧化铝，它是非反应性的，可以保护下面的纯金属。

Their mined in places like this and are then milled into a concentrate before being processed into the pure metal.

它们在这样的地方开采，然后被碾磨成精矿，再加工成纯金属。

After a couple decades of work, in 1910, they were able to isolate radium as a pure metal.

经过几十年的工作，在1910年，他们能够分离出纯金属的镭。

They're mined in places like this and have been milled into a concentrate before being processed into the pure metal.

它们在这样的地方开采，并在加工成纯金属之前被研磨成精矿。

Meanwhile, the opposite happens at the cathode rod, where metal ions from the solution gain electrons and precipitate on to the cathode as pure metal, gradually growing larger.

与此同时，相反的情况发生在阴极棒上，溶液中的金属离子获得电子并以纯金属的形式沉淀到阴极上，逐渐变大。

Princes and sovereign states have frequently fancied that they had a temporary interest to diminish the quantity of pure metal contained in their coins; but they seldom have fancied that they had any to augment it.

君主和主权国家经常幻想他们有暂时的兴趣来减少硬币中所含纯金属的数量；但是他们很少想到他们有任何东西可以增加它。