单选题 It seems oil ______ from this pipe for some time. We'll have to take the machine apart to put it right.
A. had leaked B. is leaking
C. leaked D. has been leaking

【正确答案】 D
【答案解析】[解析] 句意是：似乎油从管道泄漏已有一段时间了。我们将不得不把机器拆开修理。现在完成进行时表示在一段事件内持续进行的动作，并对现在产生一定的影响。所以正确答案是D选项。