Many language learners have a problem learning the prepositions associated with references to year, month, date and hour. The following ideas are based on the following diagram.
Understand the relationships demonstrated in the diagram and visualize the meaning of these prepositions of place and direction e.g.
 |
I'll meet AT the bus stop ON Main Street. |
| The tickets will be IN and envelope ON my desk. |
| The bus stopped AT the traffic light. |
When working on references to time use the diagram again, but think in terms of a diary or calendar, which has slots for hourly appointments. Consider the following.
 | A year is a SPACE, and so is a MONTH or a WEEK. Therefore they would require the preposition IN. e.g. IN 1997, IN August, IN the third week of August. |
| Next, you would show that the actual date is a column or line IN that week/month and thus requires ON Monday. |
| The hour would be a point on the day line and thus require AT, as in AT 6 a.m., AT 16:30 IN the afternoon |