下列不属于天体的是() A.人类的家园——地球 B.人造卫星 C.天空中飘动的云

题型:选择题

问题:

下列不属于天体的是                               (  )

A.人类的家园——地球

B.人造卫星

C.天空中飘动的云

D.星际空间的气体和尘埃

考点:地球的特殊性——存在生命的行星地球的普通性太阳辐射对地球的影响太阳活动对地球的影响
题型:选择题

单个植物细胞在体外经过诱导并培养成为完整的植物小植株的实验最好地证明了()。

A.细胞是构成有机体的基本单位

B.一切有机体均来自细胞

C.细胞是有机体生长、发育的基础

D.细胞具有遗传的全能性

题型:选择题

正畸治疗中最常见的牙周组织损伤是.()

A.牙龈炎

B.牙周袋

C.牙槽骨吸收

D.牙龈萎缩

E.以上都不是

题型:选择题

申诉期间,原机关处理决定( )。

A.不再执行

B.继续执行

C.变更执行

D.废止

题型:选择题

已知圆的周长为6.28,那么圆的面积是______.(精确到0.01)

题型:选择题

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.

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

A. cheat

B. introduce

C. provide

D. harm

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