题干

如果用动物的细胞进行克隆实验应该选择的细胞核不能于(  )

A:乳腺细胞

B:卵细胞

C:胃腺细胞

D:囊胚时期的胚胎细胞

上一题 下一题 0.0难度 选择题 更新时间:2013-03-22 09:53:36

答案(点此获取答案解析)

B

同类题1

阅读理解

    The iPhone, the iPad: each of Apple's products sounds cool and has become a fashion. Apple has cleverly taken advantage of the power of the letter “i” --- and many other brands are following suit. The BBC's iPlayer --- which allows Web users to watch TV programs on the Internet ---used the title in 2015. A lovely bear --- popular in the US and UK --- that plays music and video is called “iTeddy”. A slimmed-down version(简装本) of London's Independent newspaper was started last week under the name “i”.

    In general, single-letter prefixes(前缀) have been popular since the 1990s, when terms like e-mail first came into use.

    Most “i” products are aimed at young people and considering the major readers of independent's “i”, it's no surprise that they've selected this fashionable name.

    But it's hard to see what's so special about the letter “i”. Why not use “a”, “b”, or “c” instead? According to Tony Thorne, head of the Language Center at King's College, London, “i” works because its meaning has become ambiguous. When Apple uses “i”, no one knows whether it means Internet, information, individual or interactive, Thorne told BBC Magazines. “Even when Apple created the iPod, it seems it didn't have one clear definition,” he says.

    “However, thanks to Apple, the term is now connected with portability (轻便) .”adds Thorne.

    ※Clearly the letter “i” also agrees with the idea that the Western World is centered on the individual. Each person believes they have their own needs, and we love personalized products for this reason.

    Along with “Google” and “Microblog”, readers of BBC Magazines voted “i” as one of the top 20 words that have come to define the last ten years.

    But as history shows, people grow tired of fashions. From the 1900s to 1990s, products with “2000” in their names became fashionable as the year was connected with all things advanced and modern. However, as we entered the new century, the fashion disappeared.

同类题5

阅读理解

    Singles' Day — the Chinese opposite of Valentine's Day has turned into a massive online shopping event. It is a day when single people are supposed to buy themselves presents. But there are sociological reasons behind China's “celebration” of single life. And the imbalance could have big consequences for the country.

    There were 34 million more men than women in China in 2011. Part of that is natural – usually there are 105 boys born for every 100 girls. But the Chinese gender ratio (性别比例) at birth is much more obvious. It was 116 boys to 100 girls in 2012. The one child policy is largely to blame. Brought in to limit population expansion, the policy allows only one child per family. But because male children are seen as more valuable, as well as more likely to support their parents in old age, some parents choose to have a son over a daughter. The result is that large numbers of men will likely never get married. In fact, one study has predicted that by 2030, 1 in 5 Chinese men in their 30s will never have married, while another states that 94% of unmarried people in China are men.

    Traditionally, China has seen high levels of marriage, usually among the young. Besides, the increased education and career opportunities for women have meant that marriages are happening later. It is also traditional that women often marry men of a higher socioeconomic status than themselves. So women at the top and men at the bottom find themselves alone. One study has even suggested a link between an imbalanced gender ratio and growth in violent crime in the country.

    Singles' Day can't solve all the problems China's singles face. Indeed, it is possible that it is causing even more problems, as men resort to(诉诸于) increasingly risky lines of work to increase their chances of gaining money and thus a wife. I am worried that as money starts to overcome romance, there is evidence that China's marriage market is increasingly materialistic.