题目：
—How was the journey? Did you come back by plane or by train?
—For some reason, I came back by train. I ____ back by plane, though.
A．could have traveled
B．should travel
C．might travel
D．would have traveled
答案：
答案：A
题目分析：考查虚拟，could have done表是对过去的一种虚拟，would have done表示对将来的虚拟，句子意思“由于某种原因，我乘坐火车回来的，尽管我想乘坐飞机回来”，所以选A
点评：虚拟是个难点，做题时要注意，could have done表是对过去的一种虚拟，would have done表示对将来的虚拟。
