导致某种市场结构的存在的最重要决定因素是（）。 A.价格决策 B.进入的条件 C.产

根据短文内容，从短文后的七个选项中选出能填放空白处的最佳选项。选项中有两项为多余选

项。

Why Cats Scratch Tings

In has long been assumed that when cats scratch objects with their front paws（爪子）that they are sharpening their claws.   1 Research on cat behavior suggests that the major reason for this behavior is communication. By scratching up the bark of a tree (or the leg of your favorite chair) the cat is letting other cats or people know where she is and what she is up to.

Cats tend to pick a small number of noticeable objects in their environments to scratch such as trees, fence posts repeatedly.  2 The scratched surface leaves a highly visible mark that can be easily seen by other cats. In addition, cats have special glands （腺）in their paws so that when they make scratching movements they leave scent（气味）that the cats can smell. The fact that cats leave scent marks by making scratching movements may be the reason that cats will continue to scratch objects even after they have been declawed.  3 

We don’t know exactly what cats are communicating with their scratching. Both males and females do it. It is done inside and outside the home and even by cats living with no other cats around.  4  Cats don’t scratch up your furniture to bother you or just to be destructive, but for specific reasons, one of which is communicating. Cats also scratch to extend their bodies, during play, and possibly as a greeting or to relieve dissatisfaction when prevented from doing other things they want to do.

  5 It is easier to prevent problem scratching rather than trying to change your cat’s preference for the arm of your sofa after it has become a built up habit. Thus, the goal is to establish acceptable scratching habits by getting your cat to prefer a scratching post rather than the arm of your sofa.

A．It turns out that this is only a secondary reason.

B．This is why the tree next door looks so scratched up.

C．Cats use other parts of their bodies to communicate as well.

D．Small pieces of bark have accumulated on the ground underneath.E．Scratching can result in considerable damage, owner dissatisfaction.

F．Declawed cats may still be leaving scent marks on objects they scratch.

G．It could be a defensive warning or just a marker that announces its existence.

在处理管道故障时应遵循什么原则？

ERP系统的一个主要优势是：（）

A.程序—数据相关。

B.数据冗余。

C.不同功能数据的单独修改。

D.数据集中。

网络采购的"三分一统"措施中的"三分"是指个分开，即市场采购权、价格控制权、验收权要做到三权分离、各负其责，互不越位。"一统"即指（）

A.采购对象一律统一管理

B.供应商一律统一管理

C.合同的签约特别是结算付款一律统一管理

D.采购过程一律统一管理

液压系统防火关断电门何时关闭（）

A.主电门置OFF位时

B.发动机灭火按钮按出时

C.如果探测到火警，自动关闭