By+ specific time(before). Eat supper by 6 o’clock in the evening.
By then(before a time in the past or future). By way of(via), by the way, by far(considerably) this book is by far the best on the subject, by accident(opposite of on porpose)
In: inside a place
In a room/building, in January, in 1997, in time( not late/early enough), in the street( children were in the street)(on 16th avenue street), in the morning/afternoon/evening, in the past, in the beginning/end, in the way(obstructing)another car was in the way so he could not park his car in his driveway.(on the way= en route), once in a while(occasionally), in no time at all, in the mean time, in the middle, in the army/airforce/navy, in the row, in the event that(if)(in the event that you got an opportunity, you would be showing your talent ), in case(if), get in touch/contact with.
On: position above but in contact with an object. The records are on the table.
On a day/date: on Thursday, on January 23.on a bus/plane/train/ship/bike(….already on a plane/bike)(came by bike/ bus), on the floor(on the fifteenth floor of that building).
On time(punctual)(more specific than in time), on the corner(of two streets like 13th street and fifth avenue),on the sidewalk, on the right/left, on tv/radio, on the telephone, on the whole,(in general, all things considered), on the other hand(however/nevertheless),on sale, on foot(walking).
At: general location,(not as specific as in). Hari is at school.
At+ an address. Rohit lives at 712 16th avenue. At+ a specific time. The class begins at 3:10.