Don't forget to use...
* in + month or year- In March, In 2003
* on + date (with the year or without it) or day of the week- On April 2, On March 3, 1999, On Saturday
* at + clock time, midnight, noon- At 3:30 p.m., At 4:01, At noon
* in + season- In the summer, In the winter
* in + morning, afternoon, evening- In the morning, In the evening
* at + night- At night