话题1.Science of the stars( 恒星科学 ) 2.The development of life( 生命的发展 )3 ． Space travel and gravity( 太空旅行和重力 )功能Instructions( 指示 )语法Noun clauses as the subject( 主语从句 )重点单词astronomy ， atmosphere ， system ， chain ， theory ， globe ， violent ， unlike ， spaceship ， oxygen ， harmful ， exist ， presence ， puzzle ， gravity ， satellite ， climate ，crash ， pull ， float ， mass重点短语in time ， lay eggs ， give birth to ， in one's turn ， prevent...from ， block out ， cheer up ， now that ， break out ， watch out重点句型1.What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.2 ． This produced a chain reaction ， which made it possible for life to develop.3 ．“ Oh dear ，” I cried ，“ walking does need a bit of practice now that gravity has changed.”4 ． But when I tried to step forward ， I found I was carried twice as far as on the earth and fell over.1 ． exist vi. 存在；生存 ( 无被动式和进行时 )归纳拓展(1)There exists/existed... 某地有……；存在……exist in 存在于……exist on 靠……生活 / 生存(2)existence n ．存在；生存be in existence 存在come into existence 开始产生，成立bring into existence 使产生(3)existent adj. 存在的；现行的We can't exist without food or water.没有食物和水我们就不能生存。I can hardly exist on the wage that I'm getting.我靠我挣的工资简直难以糊口。When did the world come into existence?世界是什么时候开始存在的？There exists a good way to solve the existing problem in geography. 有一个解决目前地理问题的好办法。【链接训练】①He doesn't believe in the ________ of God.A ． life B ． exist C ． existence D ． exhibition【解析】 existence“ 存在”，符合题意。 exist 是动词，不能用在此处...
