补
练习材料：
[Day 1690 2019-05-12]
L55-1: From the earth: Greetings
Recent developments in astronomy have made it possible to detect planets in our own Milky Way and in other galaxies. This is a major achievement because, in relative terms, planets are very small and do not emit light. Finding planets is proving hard enough, but finding life on them will prove infinitely more difficult. The first question to answer is whether a planet can actually support life. In our own solar system, for example, Venus is far too hot and Mars is far too cold to support life. Only the Earth provides ideal conditions, and even here it has taken more than 4 billion years for plant and animal life to evolve. Whether a planet can support life depends on the size and brightness of its star, that is its 'sun'. Imagine a star up to 20 times larger, brighter and hotter than our own sun. A planet would have to be a very long way from it to be capable of supporting life.
朗读时间：1m11s/1m12s
任务配置： L0+L4
练习材料：
[Day 1691 2019-05-13]
L55-2: From the earth: Greetings
Alternatively, if the star were small, the life-supporting planet would have to have a close orbit round it and also provide the perfect conditions for life forms to develop. But how would we find such a planet? At present, there is no telescope in existence that is capable of detecting the presence of life. The development of such a telescope will be one of the great astronomical projects of the twenty-first century.
It is impossible to look for life on another planet using earth-based telescopes. Our own warm atmosphere and the heat generated by the telescope would make it impossible to detect objects as small as planets.Even a telescope in orbit round the earth, like the very successful Hubble telescope, would not be suitable because of the dust particles in our solar system.
朗读时间：53s/59s
任务配置： L0+L4
知识笔记：
Venus 金星 Mars 火星
Imagine a star up to 20 times larger, brighter and hotter than our own sun. 倍数的表达
练习感悟：
这篇文章很多p音 底气不足很容易嘴瓢 话说音标的学习我已经很久没有进行了……
