问题 选择题
若a<b<c,则下列结论正确的是(  )
A.|a|c>|a|bB.bc≥acC.b-c>a-cD.
1
c
1
b
1
a
答案

如果c=0,不妨设a=-2,b=-1代入各个选项第A,D错误;

由b<a根据:两边同时减去同一个数c,所得不等号的方向不变,所得到的不等式b-c>a-c成立.故C正确;

由b<a根据:两边同时乘以不等式的两边都乘(或都除以)同一个负数,必须把不等号的方向改变,所得到的不等式成立.

若c<0,b<a两边同时乘以负数c,得到:bc<ac.故B不对.

故选C.

单项选择题 A1/A2型题
单项选择题

Cooperation is the common endeavor of two or more people to perform a task or reach a jointly cherished goal. Like competition and conflict, there are different forms of cooperation, based on group organization and attitudes.
In the first form, known as primary cooperation, group and individual unite. The group contains nearly all of each individual’s life. The rewards of the group’s work are shared with each member. There is an interlocking identity of individual, group, and task performed. Means and goals become one, for cooperation itself is valued.
While primary cooperation is most often characteristic of preliterate societies, secondary cooperation is characteristic of many modem societies. In secondary cooperation, individuals devote only part of their lives to the group. Cooperation itself is not a value. Most members of the group feel loyalty, but the welfare of the group is not the first consideration. Members perform tasks so that they can separately enjoy the fruits of their cooperation in the form of salary, prestige, or power. Business offices and professional athletic teams are examples of secondary cooperation.
In the third type, called tertiary cooperation or accommodation, latent conflict underlies the shared work. The attitudes of the cooperating parties are purely opportunistic; the organization is loose and fragile. Accommodation involves common means to achieve antagonistic goals; it breaks down when the common means cease to aid each party in reaching its goals. This is not, strictly speaking, cooperation at all, and hence the somewhat contradictory term antagonistic cooperation is sometimes used for this relationship.

In the primary cooperation ______.

A.group and individual don’t have to unite

B.the group contains nearly ail of each person’s life

C.individuals work for themselves

D.people don’t value cooperation