阅读材料，回答问题

材料一：春耕夏耘，秋获冬藏……春不得避风尘，夏不得避暑热，秋不得避阴雨，冬不得避寒冻。

——晁错（西汉）《论贵粟疏》

材料二：江南……地广野丰，民勤本业，一岁或稔，则数郡忘饥。

——《宋书》

材料三：

材料四：（明代中后期）应运而生的商人是消费生活中的弄潮儿，一般的地主、官僚不能与其匹敌，积累起高额资本的商人最爱高消费……这就冲击了社会等级制度，冲击了伦理道德。

——《从明清商业广告看社会变迁》

下列各数中，最小的数是（　　）

____ ____ are they?

    “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.”