春播青饲用的燕麦，株高40～80公分时刈割青饲，留茬2～4公分；第二轮长到40～80

自去年以来，日本右翼围绕着、开展日美联合夺岛军演等系列活动，引起中国人民对巩固国家统一、维护领土主权完整等问题的极大关注。

某班同学针对，收集到了以下图片和材料，让我们一起阅读与感悟。

材料一

           图一  戚继光           图二 荷兰军队投降图       图三 沙俄侵略者侵入我国黑龙江

材料二  明清统一多民族国家的巩固，主要特点就是对外抗击外敌入侵，对内同分裂和叛乱势力作斗争，两者密切相结合。                    

                                                                            --摘编自中国历史七年级下册《教师教学用书》

请回答：

（1）图一中的戚继光是中 * * 历史上一位杰出的民族英雄，他最主要的历史贡献是什么？图二情境发生在1662年初我国的某宝岛，与此密切相关的重大历史事件是什么？

（2）17世纪中期，面对图三的情境，清政府哪位皇帝组织哪两次反击战最终双方签订了哪一条约从而解决两国的东段边界问题？

（3）论从史出，史论结合是学习历史的重要方法。材料一所涉及的史实体现了材料二的哪一观点？请你用清朝的一例史实来证明材料二的另一个观点。

（4）“学史使人明智”。请你结合上述材料和问题，联系当今中日“钓鱼岛问题”，谈谈讨论“明清统一多民族国家的巩固”这一主题的现实意义。

左主支气管（）

A.比右主支气管短

B.走向比右主支气管垂直

C.管腔较右主支气管为细

D.位于食管胸部后方

E.位于食管腹部后方

二府三司制

简述增值税专用发票认证结果及相应的处理。

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 mall 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 mall 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 mall.

Many senders of unsolicited commercial electronic mall 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 mall 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 mall cannot be solved by the government alone. The development and adoption of techno-logical 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