The train   (leave) when I  (reach) the station.a.left, reachedb.had left, reachedc.left, had reachedd.had left, had reached

The train (leave) when I (reach) the station.

To determine the correct answer, we need to consider the sequence of events in the past.

First, we know that the train leaving is a past event that happened before the second event, which is reaching the station.

Now let's analyze the options:

a. left, reached b. had left, reached c. left, had reached d. had left, had reached

Option a suggests that the train left and I reached the station at the same time, which doesn't make sense based on the given sentence structure.

Option b, "had left, reached," is the correct answer. The past perfect tense "had left" indicates that the train left before the second event, "reached."

Option c, "left, had reached," suggests that the train left and then I had reached the station, which doesn't match the given sentence structure.

Option d, "had left, had reached," implies that both events happened in the past before another event, which is not indicated in the given sentence.

Therefore, the correct answer is b. "had left, reached."