单选题 The gap between those at the lowest level and those at the highest level of income had increased ______, and is continuing to increase.
  • A. substantially
  • B. successfully
  • C. succinctly
  • D. sufficiently
【正确答案】 A
【答案解析】A项substantially“可观地，大量地”；B项successfully“成功地”；C项succinctly“简洁地，简便地”；D项sufficiently“十分地”。故应选A。