P1:P a center for metallurgy?: abundance of artifacts√ vs. Remnant of smelting furnaces×
the first metallurgists?:Old: S vs. New: pre-Columbian civilizations
P2: pollution: small debris--nearby water
CAC: PM region--sediment
P3: sediment: copper&bronze;silver
C: missing furnaces---destroyed by landslides
P1:
1-1 context: the region = center for metal inthe New Worldbut 找不到furnaces
1-2 旧观点: 17th Spaniard is the first (用新观点否定)
1-3 新观点: meta pollute local lake 1000 years ago (否定旧观点)
P2:
2-1 解释新观点中meta pollute为什么可以证明
2-2 研究方法
P3:
3-1证明新观点is right
3-2 Cooke propose: 找不到furnaces的可能原因(后面没有继续证实,一个猜想)