... night. 38/ When did you buy this car? a How far have you buy this car? b How have you bought this car? c How often do you buy this car? d How long did you buy this car? Xác định từ hoặc ... them for other things you needed. You could get meat, fruit or an axe. This way of exchanging things is called barter. Later on, people began to use money. They made money from things which ... Note : wear (v) : mặc coat (n) = áo choàng exchange (n) = trao đổi barter (n) = sự đổi chác shell (n) = vỏ sò metal (n) = kim loại copper (n) đồng đỏ tin (n) = thi c bar (n) = thanh, thỏi...