问题 单项选择题

现采用4级流水线结构分别完成一条指令的取指、指令译码和取数、运算以及送回运算结果4个基本操作,每步的操作时间依次为60ns、100ns、50ns和70ns。该流水线的操作周期应为 (50) ns。若有一小段程序需要用20条基本指令完成(这些指令完全适合于在流水线上执行),则得到第一条指令结果需 (51) ns,完成该段程序需 (52) ns。在流水线结构的计算机中,频繁执行 (53) 指令时会严重影响机器的效率。当有中断请求发生时,若采用不精确断点法,则将 (54)

A.50

B.70

C.100

D.280

答案

参考答案:C

阅读理解

Fred Astaire was born in Nebraska in 1899. Fred and his sister, Adele, learned to dance when they were very young. Their mother took them to New York to study dance. They performed in their first professional(专业的) show when Fred was ten years old and Adele was twelve. Later, as teenagers, the two danced in many shows throughout the United States. Their first big success was on Broadway in 1917.

The Astaires -- as they were known -- quickly became Broadway stars. During the nineteen twenties, they sang and danced in eleven different shows. They also performed in England. In 1932, Adele Astaire married a British man, and stopped performing. But Fred did not forego his dream. He would go on alone, in the movies.

Fred Astaire had the best skill among all dancers in history. He danced up walls and on the ceiling in the film Royal Wedding. He danced on rooftops in The Belle of New York. He danced on roller skates in Shall We Dance?

Fred Astaire made all this look easy. But it was not. He said: "Dancing is a sweaty job. You cannot just sit down and do it. You have to get up on your feet. It takes time to get a dance right, to create something memorable. I always try to get to know my dance so well that I do not have to think.”

In 1949, Fred Astaire won a special award for his film work from America's Motion Picture Academy. He also won awards from the television industry for a number of his television programs.

Fred stopped dancing in 1970. He was more than seventy years old at the time. He said a dancer could not continue dancing forever. He said he did not want to disappoint(使失望) anyone, even himself. He danced again in public only once after that. It was with another great male dancer, Gene Kelly, in the movie "That's Entertainment, Part Two".

Fred Astaire and his first wife, Phyllis, had three children. Phyllis died in 1954. Twenty-five years later, Fred married race horse rider Robyn Smith. Fred Astaire died on June 22, 1987. He was eighty-eight years old. He was called the greatest dancer in the world. His dancing was called perfect. And moviegoers everywhere will remember him as a great performer whose work will live forever in his films.

小题1:The first paragraph is mainly about_________.

A.Fred Astaire’s first success

B.Fred Astaire’s education

C.Fred Astaire’s early life

D.Fred Astaire’s family小题2:What does the underlined word “ forgo” in Paragraph 2 mean?

A.Get over

B.Set up

C.Go ahead

D.Give up小题3:What Fred Astaire said in Paragraph4 shows that ___________.

A.he knew his dance was wonderful

B.he thought dancing was not difficult

C.he devoted much time and effort to dance

D.he had ways to make people remember him小题4:What is the correct time order of the following events?

a .Fred Astaire’s first wife died.

b .Fred’s sister Adele stopped performing.

c .Fred Astaire performed with Gene Kelly in a movie.

d .Fred Astaire won an award from America’s Motion Picture Academy.

A.abcd

B.bdac

C.dcba

D.cbad

单项选择题