If the dog hadn’t woken us, we wouldn’t have noticed the fire and it _______ to the house next door．
A.could spreadB.should have spreadC.would spreadD.might have spread在线课程D
考查虚拟语气。此题为与过去事实相反的虚拟语气。其结构为：if +主语+ 过去完成时态，主句用would/could/might + have done，所以选D。