问题 选择题
下面是李刚同学在一次测验中解答的填空题,其中答对的是(  )
A.若x2=4,则x=2
B.方程x(2x-1)=2x-1的解为x=1
C.若x2+2x+k=0两根的倒数和等于4,则k=-
1
2
D.若分式
x2-3x+2
x-1
的值为零,则x=1,2
答案

A选项、x2=4,则x=±2故错误;

B选项、方程x(2x-1)=2x-1,移项得x(2x-1)-(2x-1)=0

即(2x-1)(x-1)=0

解得:x=

1
2
和1,故错误;

C选项、若x2+2x+k=0两根的倒数和等于4,设两个根是x1和x2,因而x1+x2=-2,x1•x2=k,

两根倒数的和

1
x1
+
1
x2
=
x1+x2
x1x2
=
-2
k
=4,解得k=-
1
2

D选项、若分式

x2-3x+2
x-1
的值为零,由分子的值为零得x=1或2;又x-1≠0则x≠0,因而x=2.

故选C.

阅读理解

阅读理解。

     April Fools' Day is supposed to be a day to play jokes on others in hopes of getting a good laugh and

making one feel like a fool. However, the April Fools' Day of 2010 was quite different for my mom and me.

     That day my friend Jimmy and I were playing a game. I had dropped down from a bar (横木) many

times in the past without ever having a problem, but that day the simple act of dropping to the ground became

a nightmare (噩梦). I broke my arm.

     Jimmy's dad heard my crying and rushed out to see what was going on. When he saw the problem, he

quickly put me into his truck and went inside to telephone my mom and let her know he would take me to

the hospital. As that day was April Fools' Day, Mom was not buying it and really thought all this was a big

joke. Mom was finally convinced by Jimmy's mom. When she saw me, she broke down in tears because

she felt so bad-she originally (开始) thought this was just a big prank (恶作剧).

     I guess one could compare this to the story of "The Boy Who Cried Wolf". Since I had pulled pranks

before, it is no wonder that my mom didn't believe it. I as well as my mom was made to look like a fool

that day. We both learned a valuable lesson.

1. What happened to the writer on the April Fools' Day of 2010?

A. He dreamed a terrible dream.

B. He was hurt by Jimmy.

C. He had an accident.

D. He fooled his mom with his friend.

2. Why did Jimmy's dad phone the writer's mom?

A. Because he wanted to play a joke on her.

B. Because he wanted her to go to the hospital to pay the money.

C. Because he wanted to see how deeply she loved her son.

D. Because he wanted to inform her of the accident.

3. What does the underlined sentence "Mom was not buying it" mean?

A. She didn't believe what Jimmy's dad said.

B. She would not like to pay the money.

C. She had no preparation for the bad news.

D. She thought her son deserved (应受) it.

4. Why did the writer mention the story of "The Boy Who Cried Wolf"?

A. Because he thought it was his mom's fault.

B. Because he had a lesson like that.

C. Because he was proud of his story.

D. Because he felt he was luckier than that boy.

5. From the passage we can infer that __________.

A. the writer's mom didn't care much about him

B. the writer was a dishonest person

C. the writer won't pull pranks as before

D. the writer will lose interest in games

单项选择题 案例分析题