题目

A.flew           B.through    C. comparing     D.impossible         E. clingF. less than      G.goals          H.tightly           I.strive             J.rubberImagine life as a game in which you are juggling five ballsin the air. You name them: work, family, health, friends, and spirit, andyou're keeping all of them in the air. You will soon understand that work is a__41___ ball. If you drop it, it will bounce back. But the other fourballs---family, health, friends, and spirit are made of glass. If you drop oneof these, they will be 从人类文明的起源到奴隶社会的形成，我国的原始社会经历了一个漫长的时期。据此回答下列问题(1)我国的人类文明起源于哪一原始人类？距今大约多少年？(2)写出其他两个你所知道的我国远古人类代表。(3)我国原始农耕时代的两项世界性的贡献是什么？(4)我国的人文始祖是谁？