It's all completely free too! "可知，Duolingo与其它三个apps相比，它全部是完全免费的。故选A项。

【8题详解】

细节理解题。根据第一段最后一句"You can download them for free"可知这些应用程序的共同点是可"免费下载"，因此选D项。

【点睛】每篇文章都会有一个主旨要义。主旨要义型题范围一般包括：短文标题、主题大意或段落大意等。此题型要求考生在理解文章后归纳文章要点，概括中心思想。概括主旨的方法是：先看首尾或各段开头再看全文找主题句，考生需要分析文章的篇章结构，抓住文章的开头或结尾，从而找出能概括文章的主题句。找出主题句，抓住文章主线和关键词语，归纳文章中心。如本题中的第1小题属于主旨大意题。分析整个文章可知，第一段最后两句"The list below is 4 apps that will help you learn a foreign language! You can download them for free." 本句意为"下面列出的4个应用程序将帮助你学习一门外语"！可知，本文的目的是向人们推荐语言学习应用程序，从面找到正确答案为B项。

要注意不是所有的段落都有主题句，有时主题句暗含在句中。阅读这样的文章，就需要自己根据文章的细节来分析，概括出段落的主题，从而推导出文章的主旨。分析的方法是：先弄清该段落主要讲了哪几方面的内容，这些内容在逻辑上有什么联系，然后加以归纳形成主题。

　　Twenty-five years ago, most young Britons wanted a career in law, to be a doctor, or, if they were creative enough, to take up singing. But today, things stand differently.

　　According to a survey by Tesco Mobile, a UK company, the "dream job" of young people aged between 16 and 25 in the UK is a video blogger, or "vlogger". The survey, carried out among 1,002 people, found that as much as 40 percent of them put vlogger as their number one choice on a list of ideal careers.

　　This change is undoubtedly as a result of the Internet and social media. They have made it so much easier to reach audience of the world, without having to enter a career in show business in the traditional way.

In the past, the biggest stars were trained by the Hollywood studios; now, anyone with a computer camera can become a star. Vloggers are the big stars of today because