【正确答案】 C

【答案解析】[听力原文]22-25
Have you ever played the game of five stones?. To play it you can use any small pebbles which may be lying around, but, for one of your stones, you would certainly not use a Diamond worth hundreds of pounds. Yet this is what the son of a South African farmer did in the year 1866. When he picked up what he thought was a stone, he did not know that he had become the first person to find a diamond in South Africa.
A few years later, thousands of miners were at work there. They rushed from all over the world to seek their fortunes. Most of the miners dreamed of finding one of the large stones, perhaps one like the famous Cullinan Diamond, which was found in 1905 and was as big as a man's fist. This great stone was cut into several small gems, some of which can now be seen amongst the Crown Jewels in the Tower of London.
The modem world, however, has found more important uses for its diamond than the making of jewellery. They have been put to work; for diamond is the hardest mineral foud in our earth. It can cut or polish the hardest steel or grind its way through solid rock. Only a diamond is hard enough to cut another diamond, and it is not the big stones which are needed for the drills, saws and grindingwheels. Only factories now demand the diamond dust which the early miners looked upon as useless.
Yet it is a strange fact that nature makes its hardest mineral from exactly the same sub- stance as one of its softest. This soft mineral is graphite, which is very easily broken up and is used to make the "lead" in your pencil. The name "lead" should not really be used, because graphite consists of nothing but carbon—just the same as a diamond.
本题的关键词句为Most of the miners dreamed of finding one of the large stones．由此可推断出选项[C]为正确答案。