During the Colonial days, the Iroquois had an agricultural economy basing mainly on corn with supplementary crops of pumpkins, beans, and tobacco.
  • 1、
【正确答案】 1、正确答案：basing--based    
【答案解析】解析：考查过去分词。分词短语作定语修饰economy，其作用相当于从句that is based mainly on…，故应用过去分词based而不用basing。