As the pace of life continues to increase, we are fast losing the art of relaxation. Once you are in the habit of rushing through lift, being on the go from morning till night, it is hard to slow down. But relaxation is essential for a healthy mind and body.                              

Stress is a natural part of everyday life and there is no way to avoid it. In fact, it is not the bad thing it is often supposed to be. A certain amount of stress is vital to provide motivation and give purpose to life. It is only when the stress gets out of control that it can lead to poor performance and ill health.                                                

The amount of stress a person can withstand depends very much on the individual. Some people are not afraid of stress, and such characters are obviously prime material for managerial responsibilities. Others lose heart at the first signs of unusual difficulties. When exposed to stress, in whatever form, we react both chemically and physically. In fact we make choice between "fight" or "flight" and in more primitive days the choice made the difference between life or death. The crises we meet today are unlikely to be so extreme, but however little the stress is, it involves the same response. It is when such a reaction lasts long, through continued exposure to stress, that health becomes endangered. Such serious conditions as high blood pressure and heart disease have established links with stress. Since we cannot remove stress from our lives (it would be unwise to do so even if we could), we need to find ways to deal with it.                                                               

People are finding less and less time for relaxing themselves because_____.                                                  

A. they do not know how to enjoy themselves                                       

B. they do not believe that relaxation is important for health      C. they are travelling fast all the time                                                    

D. they are becoming busier with their work  

According to the writer, the most important character for a good manager is his ________.   

A. not fearing stress                                                  B. knowing the art of relaxation         

C. high sense of responsibility                                   D. having control over performance   

Which of the following statements is true?  

A. We can find some ways to avoid stress.  

B. Stress is always harmful to people. 

C. It is easy to change the habit of keeping oneself busy with work.  

D. Different people can withstand different amounts of stress.  

In Paragraph 3, "such a reaction" refers back to_______. 

A. "making a choice between 'flight' or 'fight'"                                                         

B. "reaction to stress both chemically and physically"                                                     

C. "responding to crises quickly"

D. "losing heart at the signs difficulties" 

In the last sentence of the passage, "do so " refers to ______.     

A. "expose ourselves to stress"                               

B. "find ways to deal with stress" 

C. "remove stress from our lives"                   

D. "established links between diseases and stress"

As the pace of life continues to increase, we are fast losing the art of relaxation. Once you are in the habit of rushing through lift, being on the go from morning till night, it is hard to slow down. But relaxation is essential for a healthy mind and body.                              

Stress is a natural part of everyday life and there is no way to avoid it. In fact, it is not the bad thing it is often supposed to be. A certain amount of stress is vital to provide motivation and give purpose to life. It is only when the stress gets out of control that it can lead to poor performance and ill health.                                                

The amount of stress a person can withstand depends very much on the individual. Some people are not afraid of stress, and such characters are obviously prime material for managerial responsibilities. Others lose heart at the first signs of unusual difficulties. When exposed to stress, in whatever form, we react both chemically and physically. In fact we make choice between "fight" or "flight" and in more primitive days the choice made the difference between life or death. The crises we meet today are unlikely to be so extreme, but however little the stress is, it involves the same response. It is when such a reaction lasts long, through continued exposure to stress, that health becomes endangered. Such serious conditions as high blood pressure and heart disease have established links with stress. Since we cannot remove stress from our lives (it would be unwise to do so even if we could), we need to find ways to deal with it.                                                               

People are finding less and less time for relaxing themselves because_____.                                                  

A. they do not know how to enjoy themselves                                       

B. they do not believe that relaxation is important for health      C. they are travelling fast all the time                                                    

D. they are becoming busier with their work  

According to the writer, the most important character for a good manager is his ________.   

A. not fearing stress                                                  B. knowing the art of relaxation         

C. high sense of responsibility                                   D. having control over performance   

Which of the following statements is true?  

A. We can find some ways to avoid stress.  

B. Stress is always harmful to people. 

C. It is easy to change the habit of keeping oneself busy with work.  

D. Different people can withstand different amounts of stress.  

In Paragraph 3, "such a reaction" refers back to_______. 

A. "making a choice between 'flight' or 'fight'"                                                         

B. "reaction to stress both chemically and physically"                                                     

C. "responding to crises quickly"

D. "losing heart at the signs difficulties" 

In the last sentence of the passage, "do so " refers to ______.     

A. "expose ourselves to stress"                               

B. "find ways to deal with stress" 

C. "remove stress from our lives"                   

D. "established links between diseases and stress"

对于定义域为D的函数y=f（x），若同时满足下列条件：
①f（x）在D内单调递增或单调递减；
②存在区间[a，b]⊆D，使f（x）在[a，b]上的值域为[a，b]；那么把y=f（x）（x∈D）叫闭函数．
（1）求闭函数y=-x³符合条件②的区间[a，b]；
（2）判断函数f(x)=

3

4

x+

1

x

  (x＞0)是否为闭函数？并说明理由；
（3）若y=k+

x+2

是闭函数，求实数k的取值范围．

已知函数f(x)=

sinx

+

cosx

，(0≤x≤

π

2

)，则f（x）的值域为 ．

设

a

=(cosx，1)，

b

=(sinx，2)
（1）若

a

∥

b

，求（sinx+cosx）²的值
（2）若f(x)=(

a

-

b

)•

a

，求f（x）在[0，π]上的递减区间．