单选题 ______, after long pondering, I arrived at the following conjecture.
  • A. To date
  • B. In case
  • C. For sure
  • D. At length
【正确答案】 D
【答案解析】[解析] To date到此为止；In case万一，以免；For sure确实；At length最后，详细地。答案是D。