信号报警灯信号一般以什么表示正常（） A.灯灭 B.灯亮 C.闪灯 D.平光

(12分)⑴铁钉在氯气中被锈蚀为棕黄色物质FeCl₃，而在盐酸中却生成浅绿色的FeCl₂溶液。则在Cl₂、Cl^－、H^＋中，具有氧化性的是___________，其中氧化性最强的是_______。

⑵盐酸在不同的反应中，可以分别表现出酸性、氧化性和还原性。现有如下三个反应，请指出盐酸在三个反应中所分别表现的性质：

①Zn＋2HCl＝ZnCl₂＋H₂↑     ______________________________

②Fe₂O₃＋6HCl＝2FeCl₃＋2H₂O   ______________________________

③2HClH₂↑＋Cl₂↑           ______________________________

⑶找出⑵小题中属于氧化还原反应的化学方程式并标出电子转移的方向和数目。

袋子中装有3个白球，2个红球共5个球，每个球除颜色外都相同，从袋子中任意摸一个球，摸到白球的概率是______，摸到红球的概率是______．

Diener、larsen、leving（1985）等人提出，衡量情感应从（）方面入手。

狭义的织物风格是指（）.

A.挺括

B.滑爽

C.外观性能

D.手感

Electronic mail has become an extremely important and popular means of communication.
The convenience and efficiency of electronic mail are threatened by the extremely rapid growth in the volume of unsolicited commercial electronic mail. Unsolicited commercial electronic mail is currently estimated to account for over half of all electronic mail traffic, up from an estimated 7 percent in 2001, and the volume continues to rise. Most of these messages are fraudulent or deceptive in one or more respects.
The receipt of unsolicited commercial electronic mail may result in costs to recipients who cannot refuse to accept such mail and who incur costs for the storage of such mail, or for the time spent accessing, reviewing, and discarding such mail, or for both. The receipt of a large number of unwanted messages also decreases the convenience of electronic mail and creates a risk that wanted electronic mail messages, both commercial and noncommercial, will be lost, overlooked, or discarded amidst the larger volume of unwanted messages, thus reducing the reliability and usefulness of electronic mail to the recipient. Some commercial electronic mail contains material that many recipients may consider vulgar or pornographic in nature.
The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services, businesses, and educational and nonprofit institutions that carry and receive such mail, as there is a finite volume of mail that such providers, businesses, and institutions can handle without further investment in infrastructure. Many senders of unsolicited commercial electronic mail purposefully disguise the source of such mail.
Many senders of unsolicited commercial electronic mail purposefully include misleading information in the messages’ subject lines in order to induce the recipients to view the messages. While some senders of commercial electronic mail messages provide simple and reliable ways for recipients to reject (or ’opt-out’ of) receipt of commercial electronic mail from such senders in the future, other senders provide no such ’opt-out’ mechanism, or refuse to honor the requests of recipients not to receive electronic mail from such senders in the future, or both.
Many senders of bulk unsolicited commercial electronic mail use computer programs to gather large numbers of electronic mail addresses on an automated basis from Internet websites or online services where users must post their addresses in order to make full use of the website or service.
The problems associated with the rapid growth and abuse of unsolicited commercial electronic mail cannot be solved by the government alone. The development and adoption of technological approaches and the pursuit of cooperative efforts with other countries will be necessary as well.

Unwanted e-mail may ______.

A．cause companies to fail in business

B．cause wanted e-mail messages to lose

C．damage the credit of a company

D．do good to a small company