人教课标高一必修3Unit4Astronomythescienceofthestars单元复习摘要.ppt

复合句中充当句子主语的从句叫主语从句。 【要点精讲】 引导主语从句的词有连词that, whether；连接代词who, what, which；连接副词when, where, how, why等。如： Whether you can do it by yourself mainly depends on your ability, not your age. What I need most now is more time and more patience. When you can finish the work is of great importance. that引导主语从句时，在句中无实际意义，只起连接作用，不作句子成分。当它引导的主语从句置于句首时，that不能省略；如果用it作形式主语，而把主语从句放在句末时，从属连词that可以省略。如： That the teacher will come is certain. It is a pity (that) you made such a careless mistake. 常见由it作形式主语的句型如下： ① It+ be+ n.+主语从句。常见名词有：fact, rule, pleasure, truth, pity等。如： It is a fact that English is being accepted as an international language. It’s a rule that new members must sing a song. ② It+ be+ adj.+主语从句。常见形容词有：true, important, necessary, clear, certain等。如： It’s true that the earth is round. It was important that you rest. ③ It+v.+主语从句。常用动词：seem, appear, happen, follow等。如： It seems that I’ve made a mistake. It appeared to scientists on earth that the stars had moved. ④ It+be+v-ed+主语从句。常用过去分词：known, said, proven, asked, suggested等。如： It’s well known that Thomas Edison invented the electric lamp. It’s said that he was a spy during the war. 如果主语从句置于句首，则不能用if引导，而用whether；但如果用it作形式主语，而把主语从句放在句末时，也可以用if引导。如： Whether Tom really saw Sharon was doubtful. It was doubtful whether / if Tom really saw Sharon. 1. _____we?understand?things?has?a?lot? to?do?with?what?we?feel.? (2015·北京卷) A.?Where??B. How??C. Why??D.?When? 句意：我们如何理解事情与我们所感受的有很大关系。根据句意可知，主语从句缺少方式状语，因此选择how。故选B。? 主语从句分多种，解题时要分析原题空中缺少的是何种状语。这类题考生首先要利用主句与从句之间的逻辑关系判别，尤其是连词在从句中的功能，由于引导主语从句的连词功能有所分别，较为容易抉择，但有的连词的形式一样，但具有不同意思，这就需要考生仔细甄别，充分利用与之相关内容或与其搭配相关词语的意思。 2. Exactly?____?the?potato?was?introduced? into?Europe?is?uncertain,?but?it?was? probably?around?1565.?? (2014大纲卷) A.?whether????B.?why????C.?when????D.?how?? 句义：土豆确切是在何时被引进到欧洲还不确定，但是大约是在1565年左右。Whether表示“是否”，why表示“原因”；how表示“方式”。根据后半句it?was?probably?around?1565.可知本句谈论的是时间。故C正确。? 用适当连接词补全对话。 Lucy: Why are you looking s