A third exercise on at, on, and in, covering more fixed expressions and idiomatic uses. If you haven’t done exercise 1 yet, start there.
Grammar reviewAt, on, in — idiomatic and fixed expressions
Beyond the basic rules, at, on, and in appear in a large number of fixed expressions where the preposition must simply be memorized as part of the phrase.
Common expressions with AT: at work, at home, at school, at most, at first, at last, at the moment, at risk, at fault, at all
Common expressions with ON: on time, on sale, on holiday, on the phone, on the weekend, on purpose, on foot, on the way
Common expressions with IN: in class, in hospital (British), in a hurry, in the end, in line, in trouble, in love, in time, in the neighbourhood
Tricky pairs in this exercise: on time (punctual, exactly when expected) vs in time (not too late, before a deadline) at most (maximum) vs in all (in total) in hospital (British: as a patient) vs in the hospital (American, or visiting)