如图甲是耕地用的犁，它凝聚着劳动人民的智慧，犁是一个杠杆，犁地时，提压扶手容易改

发布时间：2017-07-21 12:06 │ 来源：www.tikuol.com

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如图甲是耕地用的犁，它凝聚着劳动人民的智慧，犁是一个杠杆，犁地时，提压扶手容易改变铧在土中的深浅；犁的铧表面很光滑，使用中可以泥土对铧的摩擦力。图乙同学们共同研究滑轮的特点：(1)他们研究定滑轮特点时，做的实验如图所示，据此可证明：使用定滑轮。

(2)他们研究动滑轮特点时，用动滑轮匀速竖直提升重物，如图所示．据此可知,使用动滑轮。

甲

乙

考点：杠杆及其五要素

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对图书管理数据库，求共借出多少种图书。请对下面的SQL语句填空：
SELECT 【15】 FROM借阅

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在使用硅酮结构密封胶前，应对标准状态的（）进行复检，检验不合格的产品不得使用。

A．邵式硬度

B．玻璃粘结性

C．相容性

D．拉伸粘结性

E．密封性幕墙

F．点支撑玻璃幕墙

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以上六种货币现汇买入价的平均水平是多少（）

A．578.145

B．515.9900

C．485.4400

D．623.1400

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SORALCHIN炼油厂工程的工程特点是（）。

A、自然环境恶劣，社会依托差

B、恐怖组织捣乱

C、异国风俗习惯

D、交通运输困难，路况差

E、工期紧迫，成本限制

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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’ o0 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.

The word "induce" in Paragraph 5 is closest in meaning to ______.

A．cheat

B．introduce

C．provide

D．harm

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