There is a considerable debate over how we should react if we detect a single from an alien civilisation.

一、核心词

1. considerable adj.相当大的、相当多的、非常可观的、相当重要的
   同义：handsome,major,significant,sizable/sizeable,substantial
   反义：inconsiderable,insignificant,insubstantial,negligible,inconsequential
2. react v.反应、反抗、起化学反应
   搭配：react to,react with
   同根：reaction
   同义：replay;respond
3. detect v.（同过探测）发现、察觉、探测
   同根：undetectable adj.未被发现的 detectable adj.可发现的、可察觉的
4. signal n.信号、电波信号 v.向...发信号、标志着
5. alien adj.外国的、相异的、外星人的 n.外星人
   搭配：alien species 外来物种、alien spaceship 外星人飞船
6. civilisation（美式s改成z）n.文明、文化

二、主题归纳-太空探索

spacecraft n.航天器、宇宙飞船
space probe 太空探测器
manned space flight 载人航天飞行

planetary adj.行星的
planetary system 行星系
solar adj.太阳的、太阳能的

habitable adj.可居住的
同义：inhabitable,livable
反义：uninhabitable,unlivable
habitat n（动植物）生长地、栖息地

三、词汇知识扩充

expense n.花钱、开销
搭配：worth the expense
spare no expense
at great/considerable/enormous expense
cut down on expense

costly adj.昂贵的、代价高昂的
搭配：costly jewelry
costly victory
costly mistake

四、句型

There is considerable debate over 备受争议
eg.Currently,there is considerable debate over the belief that violent video games may lead to criminal behavior among juveniles.
eg.There is considerable debate over the issue of whether the level or the seriousness of offences commen youth has increased in recent years.