Next, by focusing on a super-radioactive ore called pitchblende, the Curies realized that uranium alone couldn't be creating all the radiation.

接下来， 通过专注于一种超放射性矿石——沥青矿，居里夫妇意识到， 仅靠元素无法产生所有些辐射现象。

This sample is derived from here, it is pitchblende, or uraninite, a compound of oxygen and uranium, about 90% of uranium.

样本来源于此， 它是沥青矿， 矿石， 是由氧和组成的化合物，约含90%的。

By 1902, the Curies had extracted a tenth of a gram of pure radium chloride salt from several tons of pitchblende, an incredible feat at the time.

到1902年， 居里夫妇已从数吨沥青矿中提取出十分之一克纯氯化镭盐，在当时是一项不可思议的壮举。

He tested a piece of pitchblende, the principal ore of uranium, and found it to be seven hundred million years old—very much older than the age most people were prepared to grant the earth.

他测试了一块沥青矿, 发现它有七亿年的历史 - - 比大多数人准备给予地球的年龄要大得多。