【正确答案】 B

【答案解析】[解析] 14-16
It's always fun to write about research that you can actually try out for yourself.
Try this: Take a photo and upload it to Facebook, then after a day or so, note what the URL link to the picture is and then delete it. Come back a month later and see if the link works. Chances are: It will.
Facebook isn't alone here. Researchers at Cambridge University have found that nearly half of the social networking sites don't immediately delete pictures when a user requests they be removed. In general, photo-centric websites like Flickr were found to be better at quickly removing deleted photos upon request.
Why do "deleted" photos stick around so long? The problem relates to the way data is stored on large websites: While your personal computer only keeps one copy of a file, large-scale services like Facebook rely on what are called content delivery networks to manage data and distribution. It's a complex system wherein data is copied to multiple intermediate devices, usually to speed up access to files when millions of people are trying to access the service at the same time. But because changes aren't reflected across the content delivery networks immediately, ghost copies of files tend to linger for days or weeks.
In the case of Facebook, the company says data may hang around until the URL in question is reused, which is usually "after a short period of time", though obviously that time can vary considerably.

独白的第二句话即用祈使语气直接让听众Try this: Take a photo and...，即拍摄一张照片，将其上传到．Facebook上，过一两天后把照片定位链接删除，一个月后再来看这链接是否还在。选项中只有[B]项包含了delete和photo这两个中心词，因此该项就是正确答案。其余三项中，[A]中的social ties、[C]中的blogs和[D]中的websites在这一处原文中都没有涉及。

【正确答案】 C

【答案解析】在独白第四段，作者首先提出“为什么删除了的照片能留存这么久”的问题，接着进行了回答：The problem relates to the way data is stored on large websites(这一问题与大型网站储存数据的方式有关)，然后又详细分析了大型网站储存数据的方式以及因此而导致照片在删除后仍能留存几天或数周的原因。对照选项可知[C]与此意相符，因而是正确答案。其余各项都不是导致一些网站无法立即删除信息的原因。

【正确答案】 C

【答案解析】对应的信息位于独白最后一句中data may hang around until the URL in question is reused一处，即删除的数据只有在其定位链接重新被使用的时候才会消失，因此本题答案是[C]。其余各项中，[A]、[D]两项在原文中都未提及。有一部分考生误选了[B]，但该项指“建立新的链接”，不但在原文中未提及，而且答非所问。