Big apple Instances: Use apostrophes for plurals of abbreviations which have funds letters and periods: M.D.’s, C.P.A.’s. Also use apostrophes for plurals shaped from single letters: He acquired A’s and B’s on his report card. Mind your p’s and q’s. JayJay 37k33 gold badges6363 silver badges111111 bronze badges six three https://carzen.co.uk