高中英语人教版必修三课件（浙江）：Unit 4 Period Three　Gammar Writing.pptx

;语法专题;;用适当的连接词完成课文原句 1. 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.The earth became so violent that it was not clear the shape would last or not. 3. is even more important is as the earth cooled down，water began to appear on its surface.;4.It was not immediately obvious water was to be fundamental to the development of life. 5. they suddenly disappeared still remains a mystery. 6.So life will continue on the earth for millions of years to come will depend on this problem can be solved.;1.主语从句的引导词;What we need is more water.(连接代词what在从句中作need的宾语) 我们需要的是更多的水。 Whether we can live on the earth depends on whether the problem is solved.(whether虽不作成分，但有“是否”的意思) 我们能否在地球上生存就取决于这个问题能否得以解决。;2.it作形式主语 为保持句子平衡，常把主语从句后置，而用形式主语it代替。it作形式主语时常用于以下句型：;It＋系动词＋过去分词＋主语从句;1.从句的语序：在任何情况下，主语从句都用陈述语序。 Whoever of you gets here first will get the prize. 你们谁第一个到达这里谁就获奖。 2.主谓一致 (1)从句作主语时，主句的谓语一般用单数形式；但what和who引导主语从句时，有时主句谓语的数应与主句中作表语的名词保持一致。 When we shall have our sports meeting has not been decided. 我们什么时候开运动会还没有确定。 What they need are books. 他们需要的是书。;(2)如果由and连接两个或两个以上的主语从句作主语时，谓语动词用复数；由两个或多个连接词引导一个主语从句时，谓语动词用单数。 When they will start and where they will go have not been decided yet. 他们什么时候动身以及要去哪里还没定下来。 How and why he came to this city is a story of struggle and success. 他为什么及如何来到这个城市是一个充满奋斗和成功的故事。;3.whether引导的主语从句，如果用了形式主语it，引导词whether可以换成if。如果whether从句在句首或后面有or not时，不能用if替换。 Whether genetically-modified food does us harm remains to be seen. ＝It remains to be seen whether/if genetically-modified food does us harm. 转基因食物对我们是否有害有待观察。;选词填空 ① will do it doesn’t matter. ② we cannot get seems better than what we have had. ③It should be considered you come from. ④ the boy asked money from his classmates surprised his teacher. ⑤ I’ll go shopping today depends on whether I