80总吨A级航区干货船必须配备的无线电设备是（）A.一台甚高频无线电话 B.一台可携

碘是人体必需的元素之一，海洋植物如海带、海藻中含有丰富的、以碘离子形式存在的碘元素．在实验室中，从海藻里提取碘的流程和实验装置如下：

（1）指出上述提取碘的过程中有关实验操作的名称：

步骤③______，步骤⑤______．

（2）步骤④也可以先在滤液中滴入几滴稀硫酸，再加入足量H₂O₂，此时发生反应的离子方程式为：______．

（3）提取碘的过程中，可供选择的有机试剂是______．（填编号）

A．酒精          B．醋酸         C．四氯化碳         D．苯

（4）从含碘的有机溶剂中提取碘和回收有机溶剂，还需要经过蒸馏．指出右图实验装置中存在的错误之处并改正：______．

（5）进行上述蒸馏操作时，使用水浴的原因是______．

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.

According to the passage, efficiency of e-mail is threatened by ______.

A．heavy e-mail traffic

B．fraudulent e-mail messages

C．large volume of messages

D．increasing amount of unwanted e-mail

颅内压增高的“三主征”是指_________、_________、_________。

患者男性，20岁。头痛、呕吐、视力下降2个月。6个月前曾患开放性颅脑外伤、颅内感染，已治愈。腰穿测压320mmH₂O，脑脊液清亮透明。头颅CT示双侧脑室及三、四脑室扩大。

手术压力管的选择是（）

A.高压管

B.中压管

C.低压管

D.可调压管

E.普通分流管

手厥阴心包经与阴维脉交通的穴位是（）

A.劳宫

B.内关

C.外关

D.大陵

E.列缺