问题 单项选择题

一个袋子里装有三种不同颜色但大小相同的小球。红色小球上标有数字1,黄色小球上标有数字2,蓝色小球上标有数字3。小明从袋中摸出10个小球,它们的数字和是21,那么小明摸出的小球中最多可能有多少个小球是红色的( )

A.3个
B.4个
C.5个
D.6个

答案

参考答案:B

解析: 设摸出的10个球中,红色小球有a个,黄色小球b个,那么蓝色小球有(10-a-b)个。根据题干可得:
a+2b+3×(10-a-b)=21。
整理得b=9-2a,显然a最大为4。这时b=1,则蓝色小球有10-1-4=5(个)。故本题正确答案为B。

阅读理解

David Moore taught science at the City School. He needed some expensive books, and so he bought them. He put the books in his car in a quiet street. Then he went to other shops to buy something else. At six he came back to the car. One door was open – and the books were not there! David drove home to Fry Road.

On Friday people read this in the newspaper:

Books: Have you any old books? I buy old and modern books.

Open all day on Saturdays. David Moore, 26 Fry Road.

David stayed at home on Saturday. The first man came at eight. David took him to the kitchen. At half past nine another man arrived. He had a bag under his arm.

“Mr Moore?” the man asked.

“That’s right,” David said. “Can I help you?”

“I’ve got some good books. You buy books, don’t you?”

“Yes. Bring them in. Let me have a look.”

Soon the books were on the dining-table. “Come in now,” David called, “and bring the list.”

A policeman came into the dining-room. He read the names on the books and the names on the list in his hand. They were the same.

“Come with me, sir,” the policeman said to the man.

小题1:Mr Moore was a _________.

A.doctor

B.bookseller

C.teacher

D.musician小题2:Mr Moore lived _________.

A.at No. 26 Fry Road

B.in a quiet street

C.close to the police station

D.at the City School小题3:Mr Moore probably bought the books on _________.

A.Wednesday

B.Friday

C.Saturday

D.Sunday小题4:Mr Moore wrote a letter to a newspaper in order to_________.

A.tell people that he had lost some books

B.tell the police station

C.buy the expensive books

D.find who had stolen the books小题5:Mr Moore stayed at home that Saturday because_________.

A.he didn’t like to go out on Saturday

B.he didn’t need to go to school that day

C.he was waiting for the thief to come

D.he was busy with his shop

填空题