阅读《马说》一文，完成下列各题。

       世有伯乐，然后有千里马。千里马常有，而伯乐不常有。故虽有名马，只辱于奴隶人之手，骈死于槽枥之间，不以千里称也。

       马之千里者，一食或尽粟一石。食马者不知其能千里而食也。是马也，虽有千里之能，食不饱，力不足，才美不外见，且欲与常马等不可得，安求其能千里也？

       策之不以其道，食之不能尽其材，鸣之而不能通其意，执策而临之，曰：“天下无马！”呜呼！其真无马邪？其真不知马也。

阅读短文，根据短文选择正确的答案。

    Uncle Wangworks in 1 bookstore in the middle of the city. The shop is not far from his home. It is about three kilometers (公里) away. So Uncle Wang seldom (很少) 2 to work by bus. He usually goes there 3 bike, sometimes on foot. It takes him ten minutes to get there by bike and forty minutes on foot. Today his bike is broken.  He wants to walk there. Now he is having breakfast. At ten to eight, he leaves home and walks to work.  It's twenty 4 earlier than usual.  His work starts at half past eight in the morning and 5 at a quarter (一刻钟) to five in the afternoon.

目前三江平原还有大片沼泽荒地，但2000年国务院下令停止围垦，主要原因是（　　）

已知地球半径约为$6.4\times {10}^{6}m$，空气的摩尔质量约为$29\times {10}^{-3}kg/mol$，一个标准大气压约为$1.0\times {10}^{5}Pa$.利用以上数据可估算出地球表面大气在标准状况下的体积为(　　)