Harry and Ron took their copies of Unfogging the Future back down to the common room, found a table, and set to work on their predictions for the coming month. An hour later, they had made very little progress, though their table was littered with bits of parchment bearing sums and symbols, and Harry's brain was as fogged as though it had been filled with the fumes from Professor Trelawney's fire. “I haven't got a clue what this lot's supposed to mean,” he said, staring down at a long list of calculations.
“You know,” said Ron, whose hair was on end because of all the times he had run his fingers through it in frustration, “I think it's back to the old Divination standby.”
“What - make it up?”
“Yeah,” said Ron, ...
I don't quite understand the meaning of the whole sentence “I think it's back to the old Divination standby.”, especially the word 'standby'. The closest definition I got from dictionaries is:
- a person or thing ready to serve or be put into service on an emergency basis or as a substitute
But I'm not sure if it's correct. How should we understand it in this context?