The prepositions IN, ON, and AT are also used in a number of set expressions:
in a book/magazine newspaper
in charge (of)
in common (with)
in danger (of)
in detail
in existence
in the front/middle/back
in general
in part
in the past/future
in practice
in a row
in style
in theory
on a bus/train/etc.
on fire
on the other hand
on purpose
on radio/television
on the whole
at best/worst
at birth at death
at first/last
at least/most
at the moment
at once
at the peak (of)
at present
at random
