The big apple Periods: Use apostrophes for plurals of abbreviations that have capital letters and durations: M.D.’s, C.P.A.’s. Also use apostrophes for plurals formed from single letters: He received A’s and B’s on his report card. Thoughts your p’s and q’s. JayJay 37k33 gold badges6363 silver badges111111 bronze badges 6 https://carzen.co.uk