问题 选择题

为了观察门外情况,有人在门上开一小圆孔,将一块圆柱形玻璃嵌入其中,圆柱体线轴与门面垂直.从圆柱底面中心看出去,可以看到的门外入射光线与轴线间的最大夹角称作视场角.已知该玻璃的折射率为n,圆柱长为l,底面半径为r,则视场角是(    )

A.arcsin

B.arcsin

C.arcsin

D.arcsin

答案

答案:B

 如图所示.

sini=nsinr=n

i=arcsin

单项选择题
阅读理解

When 7-year-old Warren Buffet said “ I will be the richest man one day”, his friends made fun of his “daydreaming”. But ever since then the little boy has set about learning how to make money, selling drinks, delivering newspapers and buying stocks. He had already earned $ 9,000 ( equal to $ 90,000 today) by the time he graduated from high school and became a millionaire at 32.

And this month the 77-year- old, who earned his fortune by making a lot of great investment in the stock market, made his childhood dream come true. With a fortune of $ 62billion, Buffet has risen to be the world’s richest man according to Forbes Magazine.

Born in 1930, Buffet, the only son of a stockbroker, started on achieving his billion-dollar dream at an early age and was always ready to think outside the box to develop his business. At 8 he went to golf courses collecting and selling used balls.

At 11 when he sold soda pop door to door with a friend, the pair collected lids on the streets to judge which flavor was the most popular.

As a paper boy during high school, Buffet delivered two rival (竞争对手的)papers, so that even when customers canceled one of the subscriptions, he could still make a profit from the other. With his paper delivery savings, Buffet bought 162,000 square meters of farmland and collect rent.

Young Buffet stepped into the stock market at 11 but earned only $ 5. The experience taught him one of the virtues (品质) in investing: patience.

After graduating from university, Buffet started his venture with stocks with his childhood earnings and money from friends. He researched the stocks and just bought those of solid companies that were undervalued and inexpensive at the time. By sticking to companies such as American Express and Coca-cola, Buffet has become rich.

“Learning is important to Buffet’s success. He is a learning machine who can spend his entire day reading. He keeps learning, from books, street smarts and investigation, from both success and failure. In this way, he finally over achieved his aptitude ( 才能) ,” said Charlie Munger, his long-time business partner.

小题1:Which of the following questions has NOT been discussed in the selection?

A.What is Buffet’s approach to investing.

B.How do other people view Buffet.

C.How has Buffet handled hardships in his life.

D.How did Buffet make a fortune and realize his dream.小题2:With the example of delivering two rival papers in high school, the author intends to tell us that Buffet______.

A.had a good sense of business

B.was a good paper boy

C.was hard to deal with business

D.knew anything but how to make money小题3:. What did Buffet learn from his early experience of investing in stock market?

A.You never stop learning.

B.Be patient in business.

C.Only buy stocks of solid companies that are undervalued and inexpensive.

D.Stick to buying stocks in companies such as American Express and Coca-cola.小题4:. Which of the following can most probably serve as the title of the selection?

A.Buffet – Good Example for All

B.Buffet- a Newspaper Boy

C.Buffet- Investor in Stock Market

D.Buffet- a Successful Daydreamer