航空运输在短短的半个多世纪内得到了快速发展，其最大的特点和优势是由于它的舒适和安全性

已知函数f（x）对任意实数x，y，均有f（x+y）=f（x）+f（y），且当x＞0时，f（x）＞0，f（-1）=-2，求f（x）在区间[-2，1]上的值域．

在新型的师生关系中，老师和学生的地位发生了根本改变，下列对新型师生关系的认识正确的是[     ]

A．老师处于权威地位，要绝对服从于老师

B．师生关系建立在民主平等的基础上

C．学生可以置疑老师的观点

D．老师和学生之间既是师生又是朋友

一个数，如果只有（    ）和（    ）两个因数，这样的数叫做质数或（    ）。

[A] As a science, management entails the use of organized knowledge. Many of the things managers do are a result of information obtained through formal research and study. One area in which a great deal has been done is quantitative decision making or, as it is known today, management science. We know that by using certain mathematical formulas we can control inventory and project demand more accurately than by merely using trial and error.

[B] Management is the process of getting things done through people. We know that part of this process is carried out with the development of an organization structure.

[C] Yet management is also an art. Through experience the manager develops judgment and intuition, subjective factors that are useful in evaluation situations. For example, the manager may have to choose between two strategies, A and B. All research and study may indicate that neither of the two is any better than the other.

[D] Effective management is a combination of art and science. Neither should be ignored; neither ought to be relied on exclusively. In getting things done through people, management must seek the right blend of art and science. At the upper levels of the hierarchy there will be more emphasis on the former; at the lower levels there will be more emphasis on the latter.

[E] How do managers succeed in getting things done through people In order to answer this question it is necessary to break down the manager’ s job into its basic duties or functions. Management entails planning, organizing, directing, and controlling. By performing well in each of these areas the manager can get things done through people.

[F] However, what if the manager chooses strategy A on the basis of intuition and proves to be right In this case it is difficult to say precisely why the manager was able to choose so well, but there must be some special ability he or she has. This same type of ability is useful in managing people. Effective managers know when to flatter their subordinates and when to be stern. Such human behavior skills cannot be quantified; they can only be learned through experience and training.

[G] However, there is more to management than just organizing the people and the work. Objectives must be set, plans formulated, people directed, and operations controlled. In making the necessary decisions, management must rely on all the skills at its command. As a result, management is both a science and an art.

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