Occasionally one can determine whether stone tools were used in the right hand or the left, and it is even possible to assess how far back this feature can be traced.
偶尔，人们可以确定石器是用在右手还是左手上，甚至可以评估这种特征可以追溯到多远以前。
2
Fisherman Ray Turner hand-built the V-shaped stone overflow dam, in the East Branch of the Delaware River in New York.
渔民雷·特纳在纽约德拉瓦河的东支流手工建造了这个 V 字形石头溢流堰，或称鱼梁。
3
To our surprise, she'd found the tiny stone and was willing to hand it back to me.