锚重与链重的关系,一般为Wa=60Wc×10-3,则每只锚的重量约等于()锚链的重量

题型:单项选择题

问题:

锚重与链重的关系,一般为Wa=60Wc×10-3,则每只锚的重量约等于()锚链的重量。

A.50m

B.60m

C.70m

D.80m

考点:船舶结构与货运锚设备锚设备题库
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某一溴代烷A与氢氧化钠溶液混合后充分振荡,生成有机物B;A在氢氧化钠和B的混合液中共热生成一种气体C;C可由B与浓H2SO4混合加热制得,C可作果实催熟剂。则:

(1)A的结构简式为:______________________。

(2)A生成B的化学方程式:______________________。

(3)A生成C的化学方程式:______________________。

(4)B生成C的反应类型:______________________。

题型:单项选择题

(10分)可用右图所示装置制取少量乙酸乙酯。请填空:

(1)试管a中需加入浓硫酸、冰醋酸和乙醇各2 mL,正确的加入顺序及操作是___________________________________

(2)为防止a中的液体在实验时发生暴沸,可在加热前采取的措施是__________。

(3)实验中加热试管a的目的是:

①_________________________________________;

②__________________________________________;

(4)、常用同位素示踪法来确定反应物断键的情况,请用乙酸中的氧用18O,乙醇中的氧用16O写出能表示制取乙酸乙酯断键情况的化学方程式:__________________。

题型:单项选择题

结核病的主要传染源是()

A.痰涂片阳性的肺结核患者

B.痰培养阳性的肺结核患者

C.痰涂片阴性的肺结核患者

D.痰培养阴性的肺结核患者

E.儿童肺结核

题型:单项选择题

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.

题型:单项选择题

"单门"是()

A.具有一个侧枝的马鹿茸

B.具有一个主干的马鹿茸

C.具有一个侧枝的花鹿茸

D.具有一个侧枝的花鹿茸

E.没有侧枝的马鹿茸

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