Question

18．No one knows exactly how the earth began，as it happened so long ago．However，according to（61）awi dely accepted theory，the universe began with a"Big Bang"．For several billion years after the"Big Bang"，the earth was still just a cloud of dust．Then between 4.5 and 3.8 billion years ago，the dust settled into a solid globe．The earth became so （62）violent（violence） that it exploded loudly．
Water and gases（63）were produced（produce）．Water was to b e fundamental（64）tothe development of life．Many millions of years later，（65）extremely（extreme） small plants began to appear on the surface of the water．Years later，green plants began to grow on land．Then land animals，reptiles，and some huge animals，（66）called（call） dinosaurs developed．Finally human beings appeared and spread all over the earth．（67）Theyare not looking after the earth well and putting too much carbon dioxide into the atmosphe re，（68）whichprevents heat from（69）escaping （escape） from the earth into space．So whether life will continue on the earth for millions of years to come will depend on
 （70）whetherthis problem can be solved．

Answer 1

分析 没有人确切地知道地球是如何产生的，根据宇宙大爆炸的理论，宇宙大爆炸之前地球不过是一片尘埃．后来尘埃形成了一个坚实的地球，火和岩石爆炸，产生二氧化碳，氮，水蒸气和其他气体，构成了地球的大气层，随后出现了生物．然而，不断排放的过量的二氧化碳使得地球越来越热，最后生物能否继续在地球上生存还依赖于这个问题能否得到解决．

解答 61．a；考查冠词，theory是可数名词单数形式，故用a表示泛指．   
62．violent；考查形容词，本句中become是系动词，此处用形容词形式作become的表语．     
63．were produced；考查动词的时态和语态，Water and gases与动词produce是动宾关系，本讲述的是过去的事情，故用一般过去时的被动语态． 
 64．to；考查固定搭配，be fundamental to sth/doing是固定搭配，意为"对…是必要的"，其中的to是介词．   
65．extremely；考查副词，此处用副词作状语修饰整个句子． 
66．called；考查分词作定语，some huge animals与动词call是动宾关系，故用过去分词形式作后置定语． 
67．They；考查人称代词，结合上下文分析可知空格处指代上句中的human beings，在句中做主语，故用人称代词they．    
68．which；考查关系代词，分析句子结构可知这是一个定语从句，关系代词which指代上一句提到的内容．     
69．escaping；考查非谓语动词，介词from后面要跟动名词形式．    
70．whether；考查名词性从句，此处用whether引导一个宾语从句，意为"生物能否继续在地球上生存依赖于这个问题能否得到解决"．

点评 首先要通读全文，了解大意，抓住上下文语境所提供的信息，仔细分析带空格的句子，明确空格所要填的词义，词型和短语搭配，给出所要填的正确形式，然后整体阅读短文，核对答案．