Prepositional phrases

Front

at a time when many stores have a sale (selling products at a lower price)

Back

IN THE SALES

Front

when you agree to do something only if another thing also happens

Back

ON CONDITION

Front

when you do something before a particular time, you do it...

Back

IN ADVANCE

Front

if something is true; when you prepare because something might happen, you do it...

Back

IN CASE

Front

not late, punctual, early enough

Back

IN TIME

Front

taking everything into account; in general

Back

ON THE WHOLE