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 near falling (6)

97  Austere girl leaving region (6)

98  Drink: take a little drop (4)

       Down

   1  Rides so awkwardly in single file (7)

   2  Titus shows energy, tucking into porridge (5)

   3  Bribe to get African tree? (3,4)

   4  In hospital turning up to anoint old woman (6)

   5  Travel with purpose (4)

   6  Wild journey between Brazil and America? (7)

   7   Lie sprawled at first across earth floors (7)

   8   Old king’s daughter returning by ass (6)

   9   Graft as a quarrel breaks out in public space (9,6)

10   Room is a dry one, and cold (5)

11   A president, reversing direction at last, stays (6)

18   Unacceptable to retain one idea (6)

20   Why husband removed chestnut tree (4)

23   Submariner’s warning: surfacing (4)

29   Chap commonly seen in good light (3)

30   Anglo-Saxon slave seen trembling (4)

31   Tea within range (5)

32   Safe from the start, thanks to quiet hiding place (5)

33   Redeployed legion to move away (6)

34   In extremely stable wet earth raised rock plant (5)

35   Only eating melon rind? Seriously? (8)

36   Select a street restaurant (4-4)

44   Late Dame hosting women’s group, and her? (6)

45   Wood rotting among hay (8)

47   Ventilating a poor energy certificate (8)

50   As far as university, keep reading (2,2)

51   Duet with me performing hymn (2,4)

56   Made money for broadcast, potted (5)

59   Mean home to be place near Brighton, and large (5)

60   More learned how I serialise parts (5)

64   Sneer at exam (4)

67   Best family crime novel initially taken up (6)

69   Where one may save lives? Ace! (3)

72   Some breakfast choices may make us smile (7)

73   Low, about to get into dire trouble, then lower (7)

74   Fall heavily, fitting getting up (4)

75   Trout travel through burn (7)

76   Made haste with bag for plunder (7)

78   Necessity to be left out of a low joint (6)

79   Where did Zeno teach? Seconds to answer...