In, on, at
In
Time
Months/Seasons/Years
-In January
-In winter
-In 2014
Times of the day
-In the morning
-In the night
-In the afternoon
After a period (when?)
-In an hour
-In a month
-In 2 days
Place
Room/Building/Street/City/Country
-In the kitchen
-In the hospital
-In Praga Street
-In Torreon
-In France
On
Time
Days of the week
-On monday
-On saturday
Place
Objects "over"
-On the table
-On the desk
Media
-On TV
-On the radio
At
Time
For "night"
-At night
For "weekend"
-At the weekend
Place
"Next" to an object
-At the door
-At the window
-At the statue
Events
-At the party
-At the concert