In this task, you're given a context passage. Your job is to generate relevant questions that can be answered by directly referring to the passage.

Let me give you an example: Tracy slept awkwardly on their new bed and was having some pain, so Tracy cracked her neck.
The answer to this example can be: What did Tracy do with her neck?
Here is why: The question asked is relevant and can be directly answered by referring to the phrase "so Tracy cracked her neck" from the passage.

OK. solve this:
John wasn't sure she had an appointment , or was even in her office , but he found himself in front of the door at 1700 . For the life of him , he couldn't remember what time the concert was tonight . He hoped it wasn't too soon ... He had told Colleen that he would be late tonight and that he probably would step in , get something to eat , and then go back to the shuttle bay . She had said she would probably join him at some point , and leave Keith with Saril .
Answer:
What's a possible reason John couldn't remember what time the concert was ?