Christmas crossword: Double celebration

Unclued lights have something in common, nine of two words, five pairs, and one singleton.

       Across

10  Always hard to keep a maid (4)

13  Only covering one’s losing bid (6)

15  Put down women’s medieval instrument (5)

16  Follow the game secretly from chimney (5)

21  Indian wasting minutes in queue (4)

22  In recess, they are on the phone to reporters (4)

24  Yank pokes right inside basket (4)

25  Sort of breakfast originally eaten day after day (5)

27  Observe baseball player striking woman (3-7)

28  Not altogether keen about lecturer’s lectern (5)

37  Helps receive salmon, about a stone (2-5)

38  Alastair’s extended half of speech (4)

40  Fish, swimming back from the bottom of the world? (5)

41  Capital vehicle grabbed by drivers at hotel (6)

42  Animal slept briefly, dropping head and curling round (5)

46  Britain’s holding advance energy order (5)

52  Spy who didn’t mince his words? (5)

54  Lover abandoning ancient city in high Andean plain (6)

55  Bore troubled us instead (9)

58  Developer’s spine finally fails with no bracing (6)

61  American power absorbs Europe: finish! (3,2)

63  Thinking of briefly helping people on islands (13)

64  I’m a Yankee, preserving American language (5)

65  Seaweed’s very strange reach (6)

66  Painful activity, to smooth a bit of masonry (1,3,1)

68  It hurt to call round wielding a blade (6)

70  Charlotte over there say coming back (5)

71  Arrogance of team (4)

72  Ponder spending time intervening (7)

77  Roll that’s big for Taki in New York (5)

82  Kick off in the style of an Aussie native (5)

83  A-team, I note, failing in turn (3,2,1,4)

87  An aged relative in Scottish town (5)

88  Informal friend is to be quiet (4)

90  Keep worrying a snake (4)

91  Sounds like an antelope again (4)

92  Contrive to move to and fro (5)

93  Gypsy is a giant of a sort (6)

94  Stop that butterfly! (5)

95  Poet barely deletes a line (5)

96  Having got up, is...