One hundred thousand whys[youth version] 12 rolls!

The why is Chinas first this popular edition of the encyclopedia, physics, chemistry, astronomy points weather, agriculture, physiological health 5 roll, issue five hundred) that is more than copies. Chinas young childrens film version clubs in January 1961 film version. The same page shows the page 4, zoom-in (thumb and index finger operation) 5, support print directly 6, support increased save, fast browsing bookmarks 7, support to send mail books figure and text information