There are a great number of people in the world while few people are great.I think there is probably only one great person out of 10，000 at best，and most probably much less than that.

The reason why there are only few of them is that most people do not pay the price of greatness.There are so many people who want to be great，why only very few of them actually pay the price? The answer to the question explains the difference between the almost 100% people who want to be great and the much less than 0.01% who actually be so.The reason is that the road to greatness is full of pains.

Greatness requires sacrifices and there is no sacrifice without pain.The kind of sacrifices required for greatness is the ones that make the process continuously painful for long time.If you only want to be good it may be painful just every now and then，and many people can still handle it.But being great is a total difference.The pain is much deeper and it is continuous，so very few people can endure this kind of pain.Most people naturally choose things that bring pleasures to them.It's unnatural to choose pain over pleasure，let alone doing it continuously for long time.But that's what I believe is the secret to greatness: The secret to greatness is choosing pain over pleasures continuously for long time.

小题1:What is the purpose of Paragraph 1?

A．To compare.　　　　　　　　　

B．To list statistics.

C．To lead up to the topic.

D．To give information.小题2:If one person only wants to be good，what will he/she face?

A．Occasional pains.

B．Continual work.

C．Constant pains.

D．Various difficulties.小题3:What is the main idea of the passage?

A．Pleasures mean greatness.

B．Greatness equals sacrifices.

C．What's greatness.

D．Greatness lies in continuous pains.

（7分）在厚度为d，折射率为n的平板玻璃下面有一个半径为r的发光圆盘。在玻璃板的上面挡上一块圆形的纸片后，从玻璃板的上方任何位置都不能再看到发光盘。求这块圆纸片的最小半径是多大？ 若适当增加玻璃板的厚度，这块圆纸片能否挡住发光盘？为什么？(要求画出光路图分析列式求解)