263、The abbreviation of File Transfer Protocol is .

359、The chief disadvantage of a low — altitude orbit lies in the rate at which a satellite must travel.Because their period of rotation is fas/er than the rotation of the earth, satellite in lower orbits do not stay above a single point on the earth ＇ s surface.Instead, an observer, who stands on the earth looking upward through a telescope, sees such satellite move across the sky.In fact, a single satellite can complete an entire orbit in approximately 1.5 hours.

358、Maintenance begins after the system is released.As people use i t, they will suggest minor improvements and enhancements.Occasionally, bugs slip through debug and testing, and removing them is another maintenance task.

357、Positioning your firewall between an internal and external router provides little additional protection from attacks on either side, but it greatly reduces the amount of traffic the firewall server must evaluate, which can increase the firewall＇ s performance.

356、近年来,随着因特网覆盖范围的扩展,引人了一组国

355、.RF网络所用的天线在物理上可大可小,这取决于所需的通信范围。

354、检索数据的关键是记住数据存放在什么地方

353、人类不必像计算机一样地思

352、双绞线的最普通的应用是电话

351、client

350、orbit