问题 单项选择题

某大学校园网分配到的网络地址是202.17.8.0/26。若再划分出5个子网,则每个子网可分配给主机的 IP地址数是 (30)

A.6

B.14

C.30

D.62

答案

参考答案:A

解析:[要点解析] 该大学校园网分配到的网络地址202.17.8.0/26是一个C类地址块,“/26”是子网掩码255.255.255.192的缩写形式,该子网掩码是在标准子网掩码255.255.255.0的基础上扩展了2位。
由于22-2=2<5<23-2=6,其中“-2”表示主机号全0的地址被保留用于标志子网本身,以及主机号全1的地址被保留用做该子网的广播地址。可见若再划分出5个子网,还需在子网掩码255.255.255.192的基础上再借用3位用于标识子网号的掩码位,即新的子网掩码255.255.255.248。因此202.17.8.0地址的最后一个字节只剩余3位用于标识每个子网的主机,即每个子网可分配的主机地址数=23-2=6台。

填空题

B The Beatles甲壳虫乐队
The English rock music group The Beatles gave the 1960s its characteristic musical flavor and (1) a profound influence on the course of popular music, equaled by (2) performers. The guitarists John Winston Lennon, James Paul McCartney, and George Harrison; and the drummer Ringo Starr, were all born and (3) in Liverpool. Lennon and McCartney had played together in a group called The Quarrymen. With Harrison, (4) formed their own group, The Silver Beatles, in 1959, and Starr joined them in 1962. As (5) Beatles, they developed a local following in Liverpool clubs, and their first recordings, "Love Me Do" (1962) and "Please Please Me" (1963), quickly made them Britain’s top rock group. Their early music was (6) by the American rock singers Chuck Berry and Elvis Presley, but they infused a hackneyed musical (7) with freshness, vitality, and wit.
The release of "I Want to Hold Your Hand" in 1964 (8) the beginning of the phenomenon known as"Beatlemania" in the United States. The Beatle’s first US (9) aroused a universal mob adulation. Their concerts were scenes of mass worship, and their records sold (10) the millions. Their first film, the innovative A Hard Day’s Night(1964), was received enthusiastically (11) a wide audience that included many who had never before listened to rock music.
Composing their own (12) , The Beatles established the precedent for other rock groups to play their own music.Experimenting with (13) musical forms, they produced an extraordinary (14) of songs: the childishly simple "Yellow Submarine" ; the bitter social commentary of "Eleanor Rigby" ; parodies of earlier pop styles; new electronic sounds; and compositions that were scored for cellos, violins, trumpets, and sitars, as well as for conventional guitars and drums. The (15) disbanded in 1970, after the release of their final album, Let It Be, and during the 1970s (16) individual careers, On dec.8, 1980, John Lennon (17) fatally shot outside his Manhattan apartment by Mark Chapman, a 25-year-old former mental (18) who, earlier that same day, had asked Lennon for his (19) . Lennon’s murder was universally (20) with an intensity of feeling usually inspired only by political and spiritual leaders.

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