điền từ và chỗn chống 1,food ........ an importan part in the development ...... nations 2,this usually slows ...... progress,because men have little time to ....... to science , industry , government and art 3,in nations where food is ........ and easy yo get ,men have more time to spent ......activities that lead to progress,human betterement, and enjoyment of leisure 4,problem of........good food for everybody has not yet ....... solved 5,nations are begnning to put scientific knowledge to work for a ........to their food problems