北师大版高中英语模块7--Unit 20 lessons3-2
[00:04.21]when a young ex-lawyer,
[00:06.06]returning from the First World War,
[00:08.04]started work at the Mount Wilson Observatory
[00:10.39]in California.Using the most high-powered
[00:13.50]telescope of the time,he began the long slow
[00:16.57]process of exploring our galaxy.
[00:19.48]Edwin Huble was about to make astronomy's
[00:22.03]greatest breakthrough of the century.
[00:24.43]He discovered nebulae
[00:26.67]which were in fact galaxies like our won,
[00:29.28]millions of light years away from us,
[00:31.96]which proved that the universe was vastly
[00:34.16]larger than had previously been thought.
[00:36.91]Then,Hubble proved that the universe
[00:39.05]is actually expanding,
[00:40.95]and that the futher away galaxies are,
[00:42.93]the faster they move.
[00:45.50]In 1929,another far-reaching finding
[00:48.43]was made by the son of a Scottish shepherd.
[00:51.18]Before he went on holiday,
[00:52.98]Alexander Fleming left a dish
[00:54.77]with bacteria in it near the window
[00:56.93]of his laboratory.When he came back,
[00:59.14]he was just about to throw the dish away
[01:01.41]when he noticed something our of the ordinary.
[01:04.28]He double-checked and saw a blue mould
[01:06.52]in the dish around
[01:07.78]which the bacteria had been destroyed.
[01:10.76]This blue moud was in fact the natural
[01:13.41]form of pencicillin which Fleming realized
[01:15.85]was an effective way of killing bacteria.
[01:17.72]
