people in Russia don039;t celebrate christmas (at, in ,on)december they celebrate

People in Russia don't celebrate christmas (at, in ,on)december they celebrate it(at,in, on ) january 2. All my family are very busy (at ,in, on) New year 's eve 3. We were going to buy New Year gifts (at,in on ) the afternoon. 4. People believe that Santa visits their houses(at,in,on)midnight 5.(at ,in, on) Sunday morning everything was ready for the holiday