I’m always intrigued a) how easily people forget what liturgical year it is, and b) assume that the best way to find out is to ask their priest.
Having once received a phone call from a colleague wanting liturgical help, I’m doubtful that (b) is always a good assumption. The conversation went something like this:
Him: “The bishop said I could ring you for help.”
Me: “I’ll do my best”.
Him: “Well, he’s coming for a confirmation and he says he wants the readings from the lectionary.”
Me: “OK. He’ll mean those for the principal service.”
Him: “The lectionary. Is that the book you can get from SPCK?”
As I say, asking the vicar may not always be a solution.
However, there is an easier one to hand, that involves not lectionaries, nor complicated rules, nor even hierarchical pronouncements, but merely a simple bit of maths.
Take the calendar year for Ordinary Time. Divide it by 3.
If the remainder is 1, it’s Year A, the first gospel, Matthew.
If the remainder is 2, it’s Year B, the second gospel, Mark.
If it divides exactly by 3, it’s Year C, the third gospel, Luke.
Now you need never be stumped for an answer again.