原题
录音 1
What is the main topic of the talk?
AAdvantages and disadvantages of indigo for coloring jeans
BThe role of indigo in British trade and colonial expansion
CThe history of the indigo trade and indigo's reappearance as a modern commodity
DQualities that make indigo a viable commercial product
正确答案：C
解题思路
老师暂未填写解题思路。