Вставьте предлоги at , in , on 1) he is going to telephone 5 o`clock. 2)my birthday is may 21 st 3)it is always cold february 4)my father was there 1945 5)he is going to arrive monday

1. At  (всегда со временем)
2. On (т.к указано число. Без числа - in)
3. In (выше писал)
4. In (т.к год)
5. On (день недели)