const有什么作用？

阅读理解。

     American  eating  is  funny. People  in  America  eat  almost everything with a  fork. And it seems that

holding a knife in one's right hand longer than a few seconds is thought to be against good table manners.

     The system is that if it is necessary to use a knife, people take the fork in their left hands, and cut off a

piece of meat or others. Then  they  put  the knife down, transfer the fork to  their  right  hands, and then

transfer the food to their mouths with  the fork.  This is clearly funny, but it is considered  good  manners.

     There are several results of this system. First,if it is not necessary to use a knife, Americans don't  use

one, because this greatly complicates（使复杂化）things. Therefore, sometimes they will try to cut things like potatoes and even bacon with a fork. Second, since only one implement（器具）is being used, food has to be chased around the plate with the fork. Third, tables are usually laid with one knife and two forks. The outside fork is for the salad. There is no  need for foreign  visitors to follow the  American system and

try to eat the salad with only a fork, but if you do use your knife, remember to save it for the meat.

1. The word "transfer" most probably means “________”.

A. move something from one place to another    

B. make up and down

C．take away

2. From this passage we can know that _______.

A. Americans never use knives with their right hands

B. Americans eat everything with a knife

C. Americans use a fork to put food into their mouths

3. According to the passage, Americans eat potatoes with a fork probably because ______.   

A. they are too busy to use a knife    

B. there is no knife

C. they think it is complicated to use a knife

4. Which of the following about American eating is NOT true?

A. Holding a knife in one's right hand longer is not good table manners.

B. Americans will not use a knife if they don't need.

C. Foreign visitors are not allowed to use knives.

5. The best title for this passage is _______.

A. Right Hand or Left Hand    

B. Knife or Fork

C. Eating Customs in America

次氯酸可用于杀菌消毒。已知25°C时：

①HClO(aq)+OH^-(aq)= ClO^-(aq)+ H₂O(l)     ΔH＝-Q₁kJ·mol^－1

②H⁺(aq) +OH^-(aq) = H₂O(l)                ΔH＝-57.3kJ·mol^－1

下列说法正确的是

A．在25°C时，次氯酸的电离方程式及热效应可表示为：

HClO(aq)=H⁺(aq)+ClO^-(aq) ΔH＝-（57.3+Q₁）kJ·mol^－1

B．将20ml 1mol/L HClO与10ml 1mol/L NaOH混合后的溶液，一定存在:

2C(H⁺)-2C(OH^-)=C(ClO^-)-C(HClO)

C．已知酸性H₂SO₃>HClO>HSO₃^-, 则向Na₂SO₃溶液中加入HClO的离子方程式为：SO₃^2-+ HClO= HSO₃^-+ ClO^-

D．已知酸性CH₃COOH>HClO,则等浓度CH₃COONa和NaClO的混合液中： C(Na⁺)> C(ClO^-)> C(CH₃COO^-)> C(OH^-)> C(H⁺)

工人在一条街道两边栽树，每隔5米栽一棵桂花树 （两端都要栽），一共栽了226棵树，这条街道有多长？

合同分析后，应由合同管理人员向各层次管理者和企业相关部门人员作（）。

A．合同设计

B．合同交底

C．合同评价

D．合同比较

汉字的字形通常分为哪两类

A．通用型和精密型

B．通用型和专用型

C．精密型和简易型

D．普通型和提高型