【单选题】The first two stages in the development of civilized man were probably the invention of primitive weapons and the discovery of fire, although nobody knows exactly when he acquired the use of the latte...
【单选题】The first two stages in the development of civilized man were probably the invention of primitive weapons and the discovery of fire, although nobody knows exactly when people acquired the use of (1)__...
【单选题】The first two stages in the development of civilized man were probably the invention of primitive weapons and the discovery of fire, al though nobody knows exactly when acquired the use of (1)_____. T...