The statute provides for specific exemptions. The exceptions are not to be used as a subterfuge to retreat from open to executive session. Puglisi v. Sch. Comm. of Whitman, 11 Mass. App. Ct. 142, 414 N.E.2d 613) (1981) (school committee holding public hearing on discipline of school principal went into "sham" executive session to discuss character and reputation of superintendent of school system; executive session let superintendent get in private "last word" on principal; principal awarded back pay). See Dist. Att’y for Nw. Dist. v. Bd. of Selectmen of Sunderland, 11 Mass. App. Ct. 663, 418 N.E.2d 642, 644 (1981). At least in some circumstances, a subsequent open meeting on the same subject may in effect cure an improperly closed meeting. Pearson v. Bd. of Selectmen of Longmeadow, 49 Mass. App. Ct. 119, 726 N.E.2d 980 (2000); Benevolent & Protective Order of Elks, Lodge No. 65 v. Planning Bd. of Lawrence, 403 Mass. 531, 557-8, 531 N.E.2d 1233, 1249-50 (1988).