It`s...

The case was nearly over and now it was going to happen again. It was always like that and Watson was waiting for it.
Sherlock opened his mouth. „It`s-“
„You always say that,“ John suddenly interrupted him.
„Pardon?“
„You always say… It`s elementary, my dear Watson,“ Doctor said perfectly imitating Sherlock`s voice.
„Oh, really?“ Holmes appeared genuinely surprised.
„Yes, really.“
„Well, if that`s an inconvenience for you, I can change that.“
„Oh, come one. You can`t.“
„Of course, I can. I will never say that again.“
„Holmes?“
„Yes?“
„What is the grade before middle school?“
„It`s elementary, my dear Watson.“