阅读下面这首唐诗，完成后面题。

山居杂颂

饶节①

溪边小立听溪声，日到溪心衮衮②明。

独木自横人不渡，隔溪黄犊转头鸣。

【注】①饶节（1065～1120年），字德操，一字次守。抚州临川（今江西抚州市）人。中年出家，法名如璧，自号倚松道人。陆游谓其诗为“近时僧中之冠”。②衮衮，旋转翻滚的样子。

甲同学的方案：溶液  $\stackrel{BaC{l}_2溶液}{\to }$   白色沉淀  $\stackrel{加足量稀硫酸}{\to }$  沉淀不溶解

乙同学的方案：溶液  $\stackrel{\mathrm{加足量稀盐酸}}{\to }$   无沉淀  $\stackrel{BaC{l}_2溶液}{\to }$   白色沉淀

你认为哪种方案合理，为什么？

    “Who needs a shopping mall (购物中心)if you have Taobao?”says Wang Lin,28,a writer in Beijing.
    Taobao, China’s largest online shopping site （网上购物网站）,has become an important part of Wang Lin’s life. She spends lots of money on Taobao.
    A growing number of Chinese Internet users like Wang have found the joys of online shopping .Most online shoppers are students or young workers .More women shop on line then men. Clothing and home-use products（产品）are the most popular on line.
    It was reported that more than 250 billion（十亿）Yuan was spent on online shopping last year,80% through Taobao.
    Taobao means “looking for treasure” in Chinese. People can find almost everything they need on Taobao, from clothes to books, from candies to DVD players.
    You may question the security of online shopping ,Wang Lin said, “It's very safe and convenient ( 便利的).Unless you receive the products from the sellers and are satisfied with them, the shop owner will not get the money .You can also get your money back if you want to return the products.”