区分外国公司与本国公司的关键在于( )。A．公司资产 B．公司董事长的国籍 C．公司

阅读理解。

     A new problem has appeared in the world of technology- the mobile phone viruses. The first virus

called "Skulls" and "Dust", was discovered in July, 2004. Compared to computer viruses, these were

harmless, but proved that a virus could be spread across a mobile network.

     But as mobile phone technology moves forward, so do the viruses and the people who create them.

Now many people use "pocket computers" such as PDAs and "smart-phones" which can receive multimedia

messages in different forms like photos, videos, and music, and the most recent virus, "Cabir", is spread by

opening these kinds of multimedia messages. This virus gets into the mobile phone or PDA and then makes

it stop working. In only six months the virus has spread across almost 20 countries across the world-that

shows that it could easily get into millions of phones and PDAs.

     There are some viruses inside illegal (非法的) copies of games. These viruses take personal information

that is stored on someone's phone, and use it to make money for the people who sent the virus. Sometimes

the viruses have a programme that makes expensive phone calls to high cost numbers. The result is a very

high phone bill for the victim (受害者).

     In answer to this new threat (威胁), many new models of mobile phones and PDAs are now appearing

in stores with anti-virus software on them, just like computers.

1. The earliest mobile phone viruses were called

A. "Skulls"

B. "Dust"

C. "Skulls" and "Dust"

2. The earliest mobile phone viruses

A. were dangerous

B. were not dangerous

C. made phones stop working

3. What does the underlined word "multimedia" mean?

A. Photos, videos and sound.

B. Photos and videos.

C. Pocket computer.

4. How is the newest virus spread?

A. By playing games on phones.

B. By opening multimedia messages.

C. By calling expensive phone numbers.

5. What are mobile phone companies doing to stop viruses?

A. They are making fewer new phones.

B. They are putting anti-virus software on new phones.

C. They are improving mobile technology.

下列各组物质中，只用溴水就能鉴别的一组是（   ）

A．己烯、苯、苯酚

B．四氯化碳、硝基苯、乙醇

C．乙酸、乙醇、苯酚

D．乙烷、乙烯、乙炔

JZR2系列起重电动机，E级绝缘，用于工作环境温度不超过40℃的场所，按基准负载持续率（）制造。

A、20％

B、25％

C、30％

D、40％

某数据库中有员工关系E、产品关系P、仓库关系W和库存关系I，其中各个关系的属性如下。
员工关系E(employeelD，name，department)中的属性为：员工编号、姓名和部门。
产品关系P(productID，name，model，size，color)中的属性为：产品编号、产品名称、型号、尺寸和颜色。
仓库关系W(warehouselD，name，address，employeeID)中的属性为：仓库编号、仓库名称、地址和负责人编号。
库存关系I(warehouselD，productID，quantity)中的属性为：仓库编号、产品编号和产品数量。
若要求仓库关系的负责人引用员工关系E的员工编号、仓库关系W的仓库编号和产品关系P的产品编号不能为空且唯一标识一个记录，并且仓库的地址不能为空，则依次要满足的完整性约束是______。
若需得到每种产品的名称和该产品的总库存量，则对应的查询语句为：
SELELCT name SUM(quantity)
FROM P,I
WHERE______；

A．实体完整性、参照完整性、用户定义完整性
B．用户定义完整性、实体完整性、参照完整性
C．实体完整性、用户定义完整性、参照完整性
D．参照完整性、实体完整性、用户定义完整性

女职工可通过哪些途径维护自身权益？