哪种细菌在感染流行期常有健康带菌者形成（） A.伤寒沙门菌 B.痢疾志贺菌 C.脑膜

阅读理解。

     Many children use the Internet to get useful knowledge and information, and to relax in their free time.

But some of them are not using it is a good way. Here are some rules to make sure you are safe and have

fun on the Internet.

     Make rules for Internet use with your parents. For example, when you can go online, for how long and

what activities you can go online.

     Don't give your password (密码) to anyone else, and never give out the following information-your real

name, home address, age, school, phone number or other personal information.

     Check with your parents before giving out a credit card (信用卡) number.

     Never send a photo of yourself to someone by e-mail unless your parents say it's OK.

     Check with your parents before going into a chat room. Different chat rooms have different rules and

attract different kinds of people. You and your parents ought to make sure it's a right place for you.

     Never agree to meet someone you met on the Internet without your parents' permission (允许). Never

meet anyone you met online alone.

     Always remember that people online may not be who they say they are. Treat everyone online as strangers.

     If something you see or read online makes you uncomfortable, leave the site. Tell a parent or teacher right

away.

     Treat other people as you'd like to be treated. Never use bad language.

     Remember-not everything you read on the Internet is true.

1. It's good for children to ______ on the Internet.

A. give password to others

B. get useful knowledge and information

C. give out a credit card number

2. The writer tells children to ______.

A. send their photos to him

B. make rules for Internet use with parents

C. believe everything they read on the Internet

3. According to the passage, if your parents don't agree, never ______.

A. read anything on the Internet

B. relax in your free time

C. have a face-to-face meeting with anyone you met online

4. What should NOT be done when you are on line?

A. Using bad language.

B. Leaving the site if you feel uncomfortable.

C. Treating everyone online as strangers.

5. The main idea of this passage is about ______.

A. how to use computers

B. information on the Internet

C. Internet safety rules

0.00813用科学记数法表示为（　　）

A．8.13×10^-3

B．81.3×10^-4

C．8.13×10^-4

D．81.3×10^-3

以下软件中，不能直接用来编辑HTML文件的是（）。

A.记事本

B.FrontPage

C.Flash

D.Dreamweaver

（9分）按要求完成下列除杂问题

（1）FeCl₂溶液中混有少量FeCl₃，除杂试剂为          ，

离子方程式                                     ；

（2）FeCl₃溶液中混有少量FeCl₂，除杂试剂为          ，

离子方程式                                     ；

（3）Fe₂O₃中混有Al₂O₃，除杂试剂为                    ，

离子方程式                                     。

简述Java中异常处理的机制