We always go shopping on / in / at the weekend.2

We always go shopping on / in / at the weekend.
2 Lets meet on / in / at 8.30.
3 Ill give you a call on / in / at two weeks time.
4 What would you like to do at / in / on the morning?
5 They started the course on / at / in January.
6 In / On / At Christmas Day we often go for a walk.
7 Do you eat special food on / at / in Christmas?
8 What did he do in / at / on Friday?
9 I went to university in / at /on the 1990s.
10 Rebecca bought a car at / on / in July.