可以在不同程度上提高涂层的耐候性、抗渗性、耐磨性和物理机械强度等的颜料有（）。 A.

带电粒子（不计重力）以初速度V₀从a点进入匀强磁场，如图8。运动中经过b点，oa=ob。若撤去磁场加一个与y轴平行的匀强电场，仍以V₀从a点进入电场，粒子仍能通过b点，那么电场强度E与磁感强度B之比E/B为：（ ）

A．V₀

B．1

C．2V₀

D．

The Internet is not perfect. There are many problems with it.

The Internet is not organized. There is no one in charge of the Internet. It is sometimes difficult to find what you are looking for. It is also easy to get the wrong information on the “Net”.

Some businessmen cheat people on the Internet. Internet thieves can steal credit card numbers. Some advertisers send spam to e-mail boxes. E-mail boxes are often filled with these unwanted advertisements.

Illegal businesses can operate on the Internet. These businesses sell X-rated materials, cigarettes and alcohol to teenagers.

The Internet has websites with information about making bombs, breaking the law and terrorism.

Criminals can fool people, especially children, in chat rooms. They can spread poisonous information and attack new members.

The Internet is the greatest advance in communication since human emerged. But it can also like a dark alley in a dangerous part of town. Parents need to set parental controls on their children when they use the Internet. This will keep some of the bad material away from their children.

The Internet can be dangerous to computers, too. Some people who have evil intentions enjoy causing problems for other people they don’t even know. They create computer viruses. A computer can get virus by downloading a program that has a virus in it. Some virus come by e-mail.

A virus can destroy the data a person has saved in computer files. A virus can cause a computer to crash. A virus can also reproduce itself! It can send copies of itself to everyone on a person’s e-mail address list. Then these people’s will have the same problems and can’t work normally!

小题1:Why can illegal businesses operate on the Internet?

A．Because some people like to buy banned products on the Internet.

B．Because there is no one in charge of the Internet.

C．Because X-rated materials, cigarettes, alcohol and so on can be sold well on the Internet.

D．Because people who operate businesses on the Internet are criminals.小题2:Parental controls are needed when children use the Internet because________

A．poisonous information may have a bad effect on children

B．children may damage the computers

C．the Internet is always unsafe for the children

D．children can’t use the computers well小题3:We can infer from the passage that the key to solving the problems with the Internet is____________

A．to improve the computers

B．to find a medicine to kill computer viruses

C．to order people not to use the Internet

D．to improve people’s moral level（道德水平）.

（20分）某化学课外活动小组以铝屑、稀H₂SO₄、NaOH溶液为主要原料欲制备Al(OH)₃沉淀，设计了如下三种方案，见下表。阅读下表并回答下列问题：

途径	生成1 mol Al(OH)3消耗H+或OH－的物质的量/mol
	消耗H+	消耗OH－
1．Al→Al3+→Al(OH)3
2．Al→AlO→Al(OH)3
3．

（1）填写上表中空格并从节约原料的角度来分析，你认为应选择方案_________最为合理。

（2）本实验要用到NaOH溶液。某学生用已知质量y(g)的表面皿，准确称取（g）NaOH固体。他在托盘天平的右盘上放入（+ y）(g)砝码，在左盘的表面皿中加入NaOH固体，这时指针偏向右边，如图所示，下面他的操作应该是_________       使           。

（3）若称取的(g)NaOH刚好可配制0.5mol·L^－1NaOH溶液500mL。在下列配制溶液过程示意图中有错误的是（填操作序号）______________。

（4）阅读下列制备Al(OH)₃实验步骤，填写空白：

①在烧杯A中加入50mL0.5mol·LNaOH溶液，再加入足量铝屑。给溶液稍加热。其作用是：__________________________用蒸馏水把铝屑冲洗干净。称量铝屑的质量为m₁(g)。

②在盛有适量稀H₂SO₄的烧杯B中应放入___________（g）（用含m₁的式子表示）质量的铝屑，充分搅拌使铝屑反应完全。

③在盛有适量浓NaOH溶液的烧杯C中放入____________（g）（用含m₁的式子表示）质量的铝屑充分搅拌使铝屑反应完全。

④将烧杯B和烧杯C中的溶液混和观察到的现象是：_______________________________，反应的离子方程式是：___________________________

（5）过滤时某学生操作如图，请用文字说明图中错误的是：

_____________________                                                                                                                                                                                               。

（6）把沉淀转移到烧杯中，用蒸馏水洗涤三次再过滤，再洗涤、

干燥得Al(OH)₃固体质量为m₂(g)计算本实验Al(OH)₃的产率是_________________   

下列哪项不是葡萄糖注射液变色的原因是（）

A.pH值

B.灭菌温度

C.灭菌时间

D.5-羟甲基糠醛聚合物的生成量

E.葡萄糖原料的含量

将利率划分为基准利率与差别利率是按( )进行划分的。

A．利率的决定方式
B．信用行为的期限长短
C．利率的制定
D．利率与价格总水平的关系