Step4.Summing &chewing, summarizing knowledge（总结反刍 ，知识梳理）
【近义词辨析】Discuss the usages of the following similar words and finish the exercises in groups:
1. expand, extend , spread 和 stretch
【课本原句】Dr.Yuan searched for a way to increase rice harvests without expanding the area of the fields.(P10)
expand “展开，扩大”与 extend，spread和stretch是同义词。
【观察例句】A child’s vocabulary expands through reading.孩子的词汇量通过阅读得到扩大。
Why not try to expand your story into a novel?为什么不把你的故事扩展成小说呢？
As children grow older they expand their interestsand become more confident.
He expanded on his new theory.他详细地说明了自己的新理论。
There are plans to extend the no-smoking area.现已有扩大无烟区的计划。
The show has been extended for another six weeks.展览会又延长了六周。
The valley spread out beneath us.山谷在我们的下方延伸。
The bird spread its wings.鸟展开它的翅膀。
The sweater has stretched.这件毛衣给撑得变形了。
Is there any way of stretching the clothes?有什么办法能把这件衣服拉长吗？
【归纳总结】 (1)expand“展开，扩大”，不仅指尺寸的增加，还可指范围和体积的扩大。(2)extend “伸出，延伸”，指空间范围的扩大，以及长度、宽度的朝外延伸，也可指时间的延长。(3)spread“伸开，传播”，一般指向四面八方扩大传播的范围，如传播(疾病)，散布(信息)等。(4)stretch“伸展，拉长”，一般指由曲变直、由短变长的伸展，不是加长。
1．猫在火炉前伸开四肢。The cat _________ out in front of the fire.
2. 炎热的天气一直持续到十月份。The hot weather __________ to October.
As children grow older they _________ their interests and become more confident.
4. 火势不久就蔓延到邻近的建筑。The fire soon _________ to the nearby buildings.
5.铁加热会膨胀。Iron will ________ when heated.
2. thanks to, due to, owing to 和 because of
3. lead to, result in 和 result from
1.if so 如果这样, so 用在 if之后，代替前面的分句或句子，构成缩略条件句，语意可由上下文语境得知；其否定缩略形式为 if not ，表示“如果不是这样”。
Will you have a free evening tonight? ______, let’s have a dinner together.
A. If not B. Why not C. If so D. What if
2. What do you think would happen if tomorrow there was suddenly no rice to eat?
特殊疑问词+主句的疑问句序+从句的陈述句序。常用于该句型的主句的谓语动词有：think, believe, suppose, imagine, expect 等。
----I haven’t heard Henry for a long time.
----What did you suppose _____to him?
A. was happening B. to happen C. has happened D. had happened
3.would rather 宁愿，宁可
would rather do…than do…宁愿做…..不愿做…..
would do…rather than…宁愿做…..不愿做…..
would rather (that) sb did sth/ had done sth 宁愿某人…..做…..
(1)----Shall we go skating or stay at home?
A. would you rather B. do you rather C. will you rather D. should you rather
(2)I would rather you _____with us yesterday, but you left.
A. had stayed B. stay C. stayed D. have stayed
4. rather than 而不是，宁愿…..而不 常用来连接连个并列成分，表示在两者之间进行选择。prefer to do rather than do 宁可…..而不……
（1）He would rather____his life than ____damage done to state property.
A. lose; to see B. to lose; see C. to lose; to see D. lose; see
(2)Rather than _____his bicycle to work, he always prefers _____there.
A. ride; walk B. riding; walk C. ride; to walk D. to ride; walking
(3) The kid, rather than his parents,_____said to have had an accident while travelling.
A. is B. are C. will be D. would be
(3)倍数+the+名词（size, length, width, height, amount等）+of
(5)主语+谓语+by +倍数 Compared with that of last year, our coal output has increased by three times.
（1）Americans eat ____vegetables per person today as they did in 1910.
A. more than twice B. as twice as many
C. twice as many as D. more than twice as many
(2)After the new technique was introduced, the factory produced _____tractors in 1988 as the year before.
A. as twice many B. as many twice C. twice as many D. twice many as
(3)I want to buy a rope which is ______this one.
A. twice as longer as B. as twice long as C. twice the length of D. as twice as