问题 单项选择题

甲、乙、丙三人各有糖豆若干粒,甲从乙处取来一些,使自己的糖豆增加了一倍;接着乙从丙处取来一些,使自己的糖豆也增加了一倍:丙再从甲处取来一些,也使自己的糖豆增加了一倍。现在三人的糖豆一样多。如果开始时甲有51粒糖豆,那么乙最开始有多少粒糖豆

A.80

B.85

C.90

D.95

答案

参考答案:B

解析: 此题目使用逆向思维,最后每人糖粒数量数量相等设为XQ还原推理如下,丙归还x/2颗给甲,则甲数目变为3x/2;乙归还x/2颗给丙,则乙现在数目是x/2:甲再归还数目的一半给乙,则甲数目是 3X/4,乙数变成5X/4;由于3X/4等于51,可以得出X=68,由此推出乙最初数目5X/4=85。

阅读理解

     It was eleven o'clock, and Mr. Sims had just asked the class to pay attention for the fiftieth time

while he explained a math problem. Carson Webster was sitting over by the window trying to listen to

the teacher, but his mind was not on the problem Mr. Sims was discussing. Carson's mind was on a

little mouse named Millie that was busily moving around in his pocket. Millie was not very happy. At

breakfast, she had climbed into Carson's pocket and gone to sleep while Carson ate two pieces of

bread and read the newspaper. Carson had forgotten Millie was there until he was halfway in class.

Now that Millie's morning sleep was over, she was ready to exercise. Luckily for Carson, Millie was

in a pocket with a button, or he might be in serious trouble.

     "Carson?" Mr. Sims, who was usually rather strict with his students, was suddenly looking at Carson

with his eyes wide open, rolling his stick in his hand. Carson had to pay attention.

     "Could you please repeat the question?" said Carson, feeling his pocket.

     "I asked if you would agree with the statement," said Mr. Sims pleasantly.

     "Well, I'm not really attentive at the moment," said Carson. "I think I would need to give it more

consideration." Carson did not have the slightest idea as to what Mr. Sims was talking about. 

     "I see, "said Mr. Sims seriously, "Then I guess you're uncertain about whether the product of

zero by any other number is always zero?"

     "Oh, I know that," said Carson, who could feel himself turning red as a couple of kids including Bob

began to laugh. He knew his punishment would come soon. To his surprise, however, the teacher

didn't seem angry.

     "I'm so glad, "said Mr. Sims, turning back to the blackboard. "Oh, and by the way, Carson,"he

continued, "I think a cage would be a healthier place for your little friend. Would you agree with that

statement?" Just at that time, Millie let out a weak but clear cry and stuck her head out of Carson's

pocket.

     "Yes," Carson said with a smile, "I would totally agree with that statement!"

1. Which of the following is NOT a person's name?

A. Carson.    

B. Sims.    

C. Millie.    

D. Bob

2. Which of the following statements is true according to the story?

A. Bob was not the only student who laughed at Carson.

B. The little mouse escaped from Carson’s pocket in class.

C. Mr. Sims was too anxious to satisfy his students in class.

D. When Carson was in class, Millie was fast asleep in his pocket.

3. What do you think of Mr. Sims after reading the story?

A. He always gave his students punishment when they made trouble.

B. He was a teacher who was not only strict but also humorous.

C. He liked to ask his students to repeat what he said in class.

D. He was a teacher who was always kind to his students.

选择题