古代美洲文明贸易问题
1.What was traded?Why?(supply and demand)
2.What technology was needed and how did they obtain it?
3.What other things are being exchanged?(disease,goods and ideas)
4.What started the exchange?(social,religious,or political pressures)
5.What was the most significant item of the exchange?(item or idea)
6.How was the world changed by trade?
英文回答双倍悬赏（追加50＋最佳50＝100）
中文回答50
再加 50