阅读下面的文字，完成下列问题。如果有人对你说：“你已经吃过转基因食品了。”(1)你可

采集的粒子太小，计数需要在显微镜下进行．由于尘埃粒子太多，计数困难，可采用______法计数．计数时对正好落在边线上的尘埃粒子的计数原则是______．

下列属于牲畜保险除外责任的是（）。

A.疾病

B.不合理使役使其劳累致死

C.自然灾害

D.意外事故

甲状腺恶性肿瘤的超声特点（）。

A.肿瘤边界不规整呈蟹足样改变，分化程度高的癌瘤边缘整齐，有晕环

B.肿瘤边界不规整呈蟹足样改变，分化程度低的癌瘤边缘整齐，有晕环

C.肿块呈低回声，伴沙粒样钙化，后方衰减，或无变化

D.CDFI：血供极丰富，肿块内及周边有动脉频谱

E.A+C+D

Questions 91 — 100 are based on the following passage. (15 points)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.

What does unwanted e-mail messages do to the providers of the Internet services

A．Raising their cost.

B．Raising the Internet speed.

C．Improving their business.

D．Attracting investment.

离心机的传动系统采用（）润滑。

A、润滑脂

B、水

C、稀油压力循环