问题 选择题
如图所示为一磁流体发电机示意图,A、B是平行正对的金属板,等离子体(电离的气体,由自由电子和阳离子构成,整体呈电中性)从左侧进入,在t时间内有n个自由电子落在B板上,则关于R中的电流大小及方向判断正确的是(  )

A.I= ,从上向下

B.I= ,从上向下

C.I= ,从下向上

D.I= ,从下向上

答案

答案:A

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.

判断题