【题目】If the traffic so heavy, I could have been back by 6 o’clock.
A. hadn’t been B. wasn’t
C. couldn’t be D. hasn’t been
在线课程【答案】A
【解析】考查虚拟语气。句意：如果交通不那么拥挤的话，我六点以前就可以回来了。分析句子可知，本句是与过去事实相反的虚拟语气。与过去事实相反的虚拟语气，if从句要用过去完成时，而主句要用would/could/might+have done。故本题选Ａ项。