问题 选择题

某种实验中,先后要实施个程序,其中程序A只能出现在第一步或最后一步,程序B和C实施时必须相邻,请问实验顺序的编排方法共有

A.24种

B.48种

C.96种

D.144种

答案

答案:C

解:本题是一个分步计数问题,

∵由题意知程序A只能出现在第一步或最后一步,

∴从第一个位置和最后一个位置选一个位置把A排列,有 =2种结果

∵程序B和C实施时必须相邻,

∴把B和C看做一个元素,同除A外的3个元素排列,注意B和C之间还有一个排列,共有  =48种结果

根据分步计数原理知共有2×48=96种结果,选C

阅读理解

The Taj Mahal (泰姬陵) is a love story, a sad and beautiful one. If it didn’t exist, we would easily imagine that the story of its construction was simply a fairy tale. Three hundred years ago, there lived an Indian emperor called Shah Jahan. His wife was a beautiful and bright woman whom he loved greatly. Her title was Mumtazl Mahal: its shortened form Taj Mahal, means “pride of the palace”. In the year 1630 this beloved wife of the emperor died. He was so brokenhearted that he thought of giving up his throne. He decided out of his love for his wife, to build her the most beautiful tomb that had ever been seen.

He summoned the best artists and architects from India, Turkey, Persia and Arabia and finally, the design was complete. It took more than twenty thousand men working over a period of 18 years to build the Taj Mahal, one of the most beautiful buildings in the world.

The building itself stands on a marble platform 29 meters square and 6-7 meters high. Towers rise from each of the four corners. The Mahal itself soars another 61 meters into the air. It is an eight-sided building made of white marble.

The emperor planned to build an identical tomb of black marble for himself on the other side of the river connected by a silver bridge. However, his son put him into a prison in the palace before he could finish, and for the rest of his life, he could only gaze across the river at the tomb of his beloved wife.

小题1: The whole passage tells us about ______.

A.a beautiful fairy tale

B.the story of the Taj Mahal

C.white and black marble tombs made for two emperors

D.the love story of Emperor Shah Jahan and his wife小题2:Which of the following statements is NOT true about the Taj Mahal?

A.It was completed quickly owing to the efforts of the best artists and workers.

B.A lot of people took part in the building work.

C.It is a magnificent building.

D.It is a tomb for the emperor’s beloved wife.小题3: The emperor’s own tomb was designed to be ____________.

A.61 meters high

B.eight-sided

C.black-colored

D.white-colored小题4:The emperor _____________.

A.died soon after Taj Mahal died

B.was killed by his son

C.was beloved by his people

D.died after 1648

选择题