Is used when no specific point of a place is being referred to.
Examples:
(a) ...at the clinic...
(b) ...at the school...
1. Is used to refer to an enclosed area.
(a) ...in the library...
(b) ...in the office...
2. Is used for large territories such as continents, countries, states, etc. (For smaller areas, at is used)
(a) ...in Malaysia...
(b) ...in Kampung Buluh...
Both can be used for buildings. The difference is that 'at' refers to a building as an institution while 'in' refers to the building as a structure.
(a) Jenny works at a publishing house.
(b) Jenny works in a publishing house.
Is used to show that a particular place is located along a road, river, coastal line, etc.
(a) ...on Jalan Semarak...
(b) ...on Sungai Rajang...
at + a specific time on the clock
at + night
(a) We have a class at eight o'clock.
(b) We sleep at night.
in + periods longer/shorter than a day
(a) My birthday is in August.
(b) I was born in 1995.
on + a specific day of the week
on + a specific date
(a) I have badminton training on Saturday.
(b) I was born on August 16, 1995.
from (a specific time) to (a specific time)
(a) We have an extra class from 1.05 p.m. to 2.30 p.m.
(b) I have a piano lesson from 8.00 a.m. to 12.00 p.m.
Used when the first event mentioned happened first
(a) Siti took off her shoes before entering the house.
Used when the first event mentioned happened next
(a) We had lunch after the meeting.
Assess yourself by staged practices