单选题 h seems oil______from this pipe for some time. We'll have to take the machine apart to putit right.
  • A. had leaked
  • B. is leaking
  • C. leaked
  • D. has been leaking
【正确答案】 D
【答案解析】[解析] 根据句中的时间状语for some time，空格上的时态可有二种选择：现在完成时与现在完成进行时。