Prepositions are so called because they are pre-positioned before nouns to form phrases. They help to locate things in time (at midday, in the morning) and space(on the table) and to indicate direction (up the hill) and manner (with ease).
It is not always easy to know which preposition to use, particularly because sometimes the use is more metaphorical than literal: for example, if we say an assignment is 'on the table', we are describing where it literally is, but if we say that an assignment is on target, we don’t literally mean that the assignment is sitting on a target; we just mean that it is going well, 'on task', 'on the right track'. Even simple phrases such as 'up to Alaska' or 'down to Antarctica' are really metaphorical usages because we are using 'up' and 'down' to mean heading north or south.
Unfortunately, there is no easy way to learn which prepositions to use with which phrases; we just have to pick up idiomatic usage (that is, accepted everyday use) over time. However, it helps if we understand that prepositions are often used in metaphorical ways and that each preposition has its own sense of placement or direction.
The following common phrases show that sense of direction and placement; they move from easier, more literal, expressions in the first column to more difficult (perhaps metaphorical) expressions in the third column.
| at the target | at school | at the same time/at the drop of a hat/at a snail's pace |
| between slices of bread | between showers | between you and your dream/between the lines/between a rock and a hard place |
| by her side | by a small margin | by all accounts/by the skin of your teeth/by the book |
| down the hill | down the track | down a blind alley/down on your luck/down in the dumps |
| from me | from the internet | from experience/from every angle/from the horse's mouth |
| in a jar | in Brisbane | in a bad mood/in my heart of hearts/in the red |
| in the morning | in training | in time/in the end/in hot water |
| into the pool | into space | into pieces/into the unknown/into the business |
| off the table | off to the football | off the record/off her game/off his rocker |
| on the table | on the right track | on target/on a wild goose chase/on cloud nine |
| over the mountains | over the flu | over her/over the cold winter/over my dead body |
| to Perth | to the pool | to your left/to my amazement/to wild applause |
| under the bridge | under five | under a cloud/under the weather/under investigation |
| up the hill | up to Cairns | up a blind alley/up in the air/up in arms |
| with you | with your permission | with gratitude/with a grain of salt/with reluctance |
