Some people seem too think its for practicing grammar rules and learning lists of words.
一些人认为它是用来操练语法规则和学习一大堆单词。
Without danger we cannot get beyond danger.
没有危险就不能解除危险。
Once we detected a planet, we would have to find a way of blotting out the light from its star, so that we would be able to 'see' the planet properly and analyze its atmosphere.