0  373886  373894  373900  373904  373910  373912  373916  373922  373924  373930  373936  373940  373942  373946  373952  373954  373960  373964  373966  373970  373972  373976  373978  373980  373981  373982  373984  373985  373986  373988  373990  373994  373996  374000  374002  374006  374012  374014  374020  374024  374026  374030  374036  374042  374044  374050  374054  374056  374062  374066  374072  374080  447090 

7.    How can you expect to be successful ___ you won’t listen in class ?

A. in case  B. when  C. unless  D. even if

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6.    Doing your homework is a sure way to improve your test scores , and this is especially true ___ it comes to classroom tests .

A. before  B. since  C. when  D. after

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5.    To keep healthy , most retired old people ___ jogging as a regular form of exercise .

A. take up  B. make up  C. carry out  D. hold out

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4.    It is not so difficult to learn program well. ___ you need is patience and persistence .

A. Something  B. All  C. Both  D. Everything

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3.    --Will you be ___ this afternoon , John ?

--It depends. I’m afraid I’ll be called in by my manager.

  A. suitable  B. convenient  C. accurate  D. available

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2.    After the long journey , the Smiths returned home , ____ .

A. safe but tired  B. safely but tired  C. safe and tiring  D. safely and tiring

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第一节:单项填空(共20小题:每小题0.5分,满分10分)

从A、B、C、D四个选项中,选出可以填入空白处的最佳选项,并在答题卡上将该选项标号涂黑。

1.    In ___ preparation for the launching of Chang’e I , scientists need ___ knowledge of weather changes .

A. the ; the  B. a  ; /  C. / ; a  D. the ; a

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导入课题

教学环节
教学内容
师生互动
设计意图
提出问题
示例1:数集的拓展
示例2:方程(x – 2) (x2 – 3) = 0的解集. ①在有理数范围内,②在实数范围内.
学生思考讨论.
 
挖掘旧知,导入新知,激发学习兴趣.
形成概念
1.全集的定义.
如果一个集合含有我们所研究问题中涉及的所有元素,称这个集合为全集,记作U.
示例3:A = {全班参加数学兴趣小组的同学},B = {全班设有参加数学兴趣小组的同学},U = {全班同学},问UAB三个集关系如何.
2.补集的定义
补集:对于一个集合A,由全集U中不属于集合A的所有元素组成的集合称为集合A相对于全集U的补集,记作UA.
UA = {x | xU,且},
Venn图表示

师:教学学科中许多时候,许 多问题都是在某一范围内进行研究. 如实例1是在实数集范围内不断扩大数集. 实例2:①在有理数范围内求解;②在实数范围内求解. 类似这些给定的集合就是全集.
师生合作,分析示例
生:①U = AB
U中元素减去A中元素就构成B.
师:类似②这种运算得到的集合B称为集合A的补集,生师合作交流探究补集的概念.
合作交流,探究新知,了解全集、补集的含义.
应用举例
深化概念
例1  设U = {x | x是小于9的正整数},A = {1,2,3},B = {3,4,5,6},求UAUB.
例2  设全集U = {x | x是三角形},A = {x|x是锐角三角形},B = {x | x是钝角三角形}. 求ABU (AB).
学生先尝试求解,老师指导、点评.
例1解:根据题意可知,U = {1,2,3,4,5,6,7,8},所以  UA = {4, 5, 6, 7, 8},
    UB = {1, 2, 7, 8}.
例2解:根据三角形的分类可知  AB =
AB = {x | x是锐角三角形或钝角三角形},
U (AB) = {x | x是直角三角形}.
加深对补集概念的理解,初步学会求集合的补集.
性质探究
补集的性质:
A∪(UA) = U
A∩(UA) =.
练习1:已知全集U = {1, 2, 3, 4, 5, 6, 7},A={2, 4, 5},B = {1, 3, 5, 7},求A∩(UB),(UA)∩(UB).
总结:
(UA)∩(UB) = U (AB),
(UA)∪(UB) = U (AB).
师:提出问题
生:合作交流,探讨
师生:学生说明性质①、②成立的理由,老师点评、阐述.
师:变式练习:求AB,求U (AB)并比较与(UA)∩(UB)的结果.
解:因为UA = {1, 3, 6, 7},UB = {2, 4, 6},所以A∩(UB) = {2, 4},
(UA)∩(UB) = {6}.

能力提升. 探究补集的性质,提高学生的归纳能力.
应用举例
例2  填空
(1)若S = {2,3,4},A = {4,3},则SA =     .
(2)若S = {三角形},B = {锐角三角形},则SB =      .
(3)若S = {1,2,4,8},A =,则SA =     .
(4)若U = {1,3,a2 + 3a + 1},A = {1,3},UA = {5},则a    .
(5)已知A = {0,2,4},UA = {–1,1},UB = {–1,0,2},求B =
    .
(6)设全集U = {2,3,m2 + 2m – 3},A = {|m + 1| ,2},UA = {5},求m.
(7)设全集U = {1,2,3,4},A = {x | x2 – 5x + m = 0,xU},求UAm.
 
师生合作分析例题.
例2(1):主要是比较AS的区别,从而求SA .
例2(2):由三角形的分类找B的补集.
例2(3):运用空集的定义.
例2(4):利用集合元素的特征.
综合应用并集、补集知识求解.
例2(7):解答过程中渗透分类讨论思想.
例2(1)解:SA = {2}
例2(2)解:SB = {直角三角形或钝角三角形}
例2(3)解:SA = S
例2(4)解:a2 + 3a + 1 = 5,
a = – 4或1.
例2(5)解:利用韦恩图由AUA 先求U = {–1,0,1,2,4},再求B = {1,4}.
例2(6)解:由题m2 + 2m – 3 = 5且|m + 1| = 3,
解之m = – 4或m = 2.
例2(7)解:将x = 1、2、3、4代入x2 – 5x + m = 0中,m = 4或m = 6,
m = 4时,x2 – 5x + 4 = 0,即A = {1,4},
又当m = 6时,x2 – 5x + 6 = 0,即A = {2,3}.
故满足条件:UA = {1,4},m = 4;UB = {2,3},m = 6.
进一步深化理解补集的概念. 掌握补集的求法.
归纳总结
1.全集的概念,补集的概念.
2.UA ={x | x∈U,且}.
3.补集的性质:
①(UA)∪A = U,(UA)∩A =
U= UU =
③(UA)∩(UB) = (AB),
 (UA)∪(UB) = (AB)
师生合作交流,共同归纳、总结,逐步完善.
引导学生自我回顾、反思、归纳、总结,形成知识体系.
课后作业
1.1 第四课时习案
学生独立完成
巩固基础、提升能力

备选例题

例1  已知A = {0,2,4,6},SA = {–1,–3,1,3},SB = {–1,0,2},用列举法写出集合B.

[解析]∵A = {0,2,4,6},SA = {–1,–3,1,3},

S = {–3,–1,0,1,2,3,4,6}

SB = {–1,0,2},∴B =(SB) = {–3,1,3,4,6}.

例2  已知全集S = {1,3,x3 + 3x2 + 2x},A = {1,|2x – 1|},如果SA = {0},则这样的实数x是否存在?若存在,求出x;若不存在,请说明理由.

[解析]∵SA = {0},∴0∈S,但0A,∴x3 + 3x2 + 2x = 0,x(x + 1) (x + 2) = 0,

x1 = 0,x2 = –1,x3 = –2.

x = 0时,|2x – 1| = 1,A中已有元素1,不满足集合的性质;

x= –1时,|2x – 1| = 3,3∈S; 当x = –2时,|2x – 1| = 5,但5S.

∴实数x的值存在,它只能是–1.

例3  已知集合S = {x | 1<x≤7},A = {x | 2≤x<5},B = {x | 3≤x<7}. 求:

(1)(SA)∩(SB);(2)(AB);(3)(SA)∪(SB);(4)(AB).

[解析]如图所示,可得

AB = {x | 3≤x<5},AB = {x | 2≤x<7},

SA = {x | 1<x<2,或5≤x≤7},SB = {x | 1<x<3}∪{7}.

由此可得:(1)(SA)∩(SB) = {x | 1<x<2}∪{7};

(2)(AB) = {x | 1<x<2}∪{7};

(3)(SA)∪(SB) = {x | 1<x<3}∪{x |5≤x≤7} = {x | 1<x<3,或5≤x≤7};

(4)(AB) = {x | 1<x<3}∪{x | 5≤x≤7} = {x | 1<x<3,或5≤x≤7}.

例4  若集合S = {小于10的正整数},,且(SA)∩B = {1,9},AB = {2},(SA)∩(SB) = {4,6,8},求AB.

[解析]由(SA)∩B = {1,9}可知1,9A,但1,9∈B

AB = {2}知,2∈A,2∈B.

由(SA)∩(SB) = {4,6,8}知4,6,8A,且4,6,8B

下列考虑3,5,7是否在AB中:

若3∈B,则因3AB,得3A. 于是3∈SA,所以3∈(SA)∩B

这与(SA)∩B = {1,9}相矛盾.

故3B,即3∈(SB),又∵3(SA)∩(SB),

∴3(SA),从而3∈A;同理可得:5∈A,5B;7∈A,7B.

A = {2,3,5,7},B = {1,2,9}.

评注:此题Venn图求解更易.

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通过示例,尝试发现式学习法;通过示例的分析、探究,培养发现探索一般性规律的能力.

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重点:补集概念的理解;难点:有关补集的综合运算.

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