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Unit 4 Astronomy:The science of the stars 第4单元 行星的科学(重点句型)--人教版新课标必修三第四单元学案

unit 4  astronomy:the science of the stars 第4单元 行星的科学(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. 随后它会变成什么没人能知道,直到38~45 亿年前,这团尘埃才慢慢地形成一个固体的球状物。

what it was to become ...是what 引导的主语从句,what 在从句中作become 的宾语。

what surprised everybody was that he didn’t come to the meeting. 使大家惊奇的是他竟没有参加会议。

what he did added to our difficulty. 他所做的增加了我们的困难。

“be+动词不定式”在本句中表示按照计划、安排将要发生的动作。

when are they to hand in their plan? 他们的计划什么时候交上来?

you are to do your homework before you watch tv. 你得做完了作业才能看电视。

联想拓展

“be+to”还可以表示以下含义:

表示可能性,相当于can,主要用于疑问句和否定句。表示命令,意为“必须,不得不”,意思等同于must, have to,表示假设。表示“命运注定……”,通常用于过去时。

how am i to know what has become of him? 我怎么知道他的遭遇如何呢?

certain skills must be learned if one is to use english well.如果想要用好英语,某些技巧是必须学的。

he was never to see his wife again. 他注定再也见不到他妻子了。

were we to offer you more money, would you stay? 如果我们给你加钱,你愿意留下吗?

单项填空

in dry weather the flowers will have to be watered if they        . 
a. have survived   b. are to survive
c. would survive   d. will survive

 

解析:选b。考查真实条件句。are to survive在此处并不表示将来,而表示“期望”。

2. but when i tried to step forward, i found i was carried twice as far as on the earth and fell over.而当我试着向前迈步的时候,我发觉我被送出去很远,步子的跨度竟是地球上的两倍,因而我摔倒了。

twice as ...as ... 是……的两倍

英语中的倍数表达法:

倍数+as +adj./adv.+as 是……的几倍

倍数+adj./adv.的比较级+ than 比……(多/大)几倍

倍数+ the +表示长度/高度/宽度等的名词+ of是……长度/高度/宽度的几倍,此结构中常用的名词有:size, height, weight, length, width, depth等。

this ruler is three times as long as that one.=this ruler is twice longer than that one. =this ruler is three times the length of that one. 这把尺子是那把的三倍长。

there are four times as many students as we expected. 到的学生是我们预计的五倍。

(1)翻译句子

这个房子是那个的三倍大。

(2)完成句子

到的客人是我们预计的两倍。

there are        we expected .

答案:(1)this house is three times as big as that one./this house is twice bigger than that one./this house is three times the size of that one.

           (2)twice as many guests as
 

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