By the time we arrived at the station the train has left.A B C DD has left改为had left.

问题补充：

By the time we arrived at the station, the train has left.

A B C DD has left改为had left.

答案：

(答案→)D has left改为had left.

解析：因为从句用了一般过去时，这里的动词要比前一动作前，所以用过去完成时。