题干

下列关于细胞结构和功能的叙述中,正确有几项(  )

①除了细胞之间形成通道外,细胞之间的信息交流都要通过细胞膜上的受体来实现;②在制备细胞膜的实验中,红细胞一般要先用适量的生理盐水稀释;③用丙酮从鸡的红细胞中提取脂质,在水面铺展成单分子层,面积恰为红细胞表面积的两倍;④中心体是仅由两个相互垂直的中心粒组成的细胞器;⑤生物膜系统是细胞内所有的膜结构的统称,包括叶绿体类囊体薄膜;⑥缺氧状态,叶肉细胞产生的一分子CO2进入相邻细胞的叶绿体内,穿膜层数是6层;⑦电镜下观察植物叶肉细胞的细胞核,可以看到的主要结构有核膜、核仁和染色体.

A:二项

B:三项

C:四项

D:五项

上一题 下一题 0.0难度 选择题 更新时间:2012-07-23 04:13:25

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A

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    Imagine that you're the creator and show runner of the newest comedy show on television. Only it isn't so popular yet, and your live Studio audience isn't giving you the big laughs the show deserves. Do you film the show all over again, hoping that this time the audience will laugh? Or is there another option for making a joke sound funnier than it was received?

    Sweeten(改善) the sound by adding a laugh track! “Sweetening,” or the addition of sound effects such as laughs, screams, and other audience-produced noises to the audio track of a TV show, has been used since the 1940s to produce the appearance, or rather the sound, of an engaged and entertained response to a show's comedy. Laugh tracks came into existence as not only a solution, and sometimes replacement, for an unengaged live audience but also as a way to engage an at-home audience into a more-traditional, public, and theaterlike experience. Adding a laugh track to a television show makes the viewers at home feel much less like they're sitting on a couch staring at the television screen and much more like they're in a room full of laughing happy people to varying degrees of success.

    Though the art of sweetening has risen and fallen in popularity over the past 60 years, credit for its creation and continued use is owed to laugh-track pioneer and sound engineer Charles Douglass. Douglass was the first to develop, in 1953, a machine for producing “canned laughter”, accessible at the push of a button or pull of a lever (操纵杆). Despite being artificial, sensibly edited laugh tracks are found by television studios to bring about a positive audience response, as their use is usually accompanied by higher ratings and increased audience memory. Though some television audiences may disagree with the value of the laugh track, the cheerful and repetitive sound holds a permanent place in the history and future of television comedy.