国际主流的信用风险计量方法经历了哪几个主要发展阶段( ) A．专家判断法 B．信用

下列各句中，没有语病的一句是

A．海峡两岸高层人士50年来首次公开、直接的历史性接触，开启了两岸协商谈判解决问题的大门，这一事件必将载入两岸关系史册。

B．这家工厂虽然规模不大，但曾两次荣获省科学大会奖，三次被授予省优质产品称号，产品远销全国各地和东南亚地区。

C．这次网络短训班的学员，除北大本校人员外，还有来自清华大学等15所高校的教师、学生和科技工作者也参加了学习。

D．中国斯诺克神奇小子丁俊晖虽然再次无缘世界锦标赛正赛，但他的防守控制能力和坚韧意志均有较大提高，相信他明年一定会梦想成真。

治疗猩红热的抗生素首选（）。

A.头孢曲松

B.阿米卡星

C.万古霉素

D.庆大霉素

E.青霉素G

新生儿溶血病换血下列哪种血液制品可选择

A.AB型红细胞、O型血浆

B.O型红细胞、AB型血浆

C.AB型红细胞、AB型血浆

D.O型红细胞、O型血浆

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.

"Pornographic" in Paragraph 3 probably means ______.

A．decent

B．instructional

C．sexual

D．commercial

（）应每月测1次。

A、站场绝缘

B、阴极电位

C、沿线保护电位

D、管道防腐层