横向
1
Metal that replaced bronze in tools
4
Object made by humans from the past
5
Long and distinct period of history
6
Alloy of copper and tin used in early tools
7
Period of one hundred years
9
Formal agreement between nations
13
Person who buys and sells goods
纵向
2
Belonging to a very old period
3
Sudden overthrow of a government
8
Legislative body in ancient Rome
10
Medieval land-for-service system
11
Person with no fixed home
12
Period of ten years