English and ESL Instructor
To indicate times of day, we use at:
I leave for school at 8 a.m. everyday.
For days of the week, the proper preposition is on:
I will be going to my friend's birthday party on Saturday.
When mentioning a year, it is in:
The Second World War ended in 1945.
If a specific date is used, the proper preposition is on:
On December 7, 1941, the Imperial Japanese Navy attacked Pearl Harbor.
When referring to a period of time, use during:
The Industrial Revolution happened during the mid to late 19th century.
During the Great Depression, the Roosevelt Administration created many new types of welfare.