单选题 (Leading) scientists are often the (kinds of person) who (have enjoyed) intellectual challenges (all their lives).
  • A. Leading
  • B. kinds of person
  • C. have enjoyed
  • D. all their lives


【正确答案】 B
【答案解析】名词单复数错误，应改为kind of persons。主语scientists是复数，其表语也应是相应的 persons。由于scientists只是一类人，kind用单数就行了。