单选题 Corn originated in the New World and thus was not known in Europe until Columbus found it ______ in Cuba.
  • A. being cultivated
  • B. having cultivated
  • C. has been cultivated
  • D. cultivating
【正确答案】 A
【答案解析】首先，是人们cultivate“种植”玉米，也就是说corn是被cultivated的，因此用主动形式是错误的，据此排除B和D。其次，cultivate在本句中是作found的宾语补足语，如果found后面接从句的话，时态应该是过去时it was cultivated in Cuba。所以只有A符合语法要求。