Most native speakers of English have no problem with prepositions. The system or grammar gets absorbed and understood when children are very young. Years ago, I worked on BBC Television's 'Playschool' and I used to watch 'Sesame Street' with my children and I could never understand why we and they spent so much time making up stories and sketches about 'in' and 'on' or 'to' and 'from' and the like. I've never had a sense that children 'get these wrong' without being taught. Perhaps they do, and I've missed it.
...the moment we start chopping up language into grammatical categories, we run into difficulties. The reason for this is that the categories are nearly always 'vertical' (see earlier blogs for this), but we speak and write language horizontally. In other words we are sticking words, phrases, clauses and sentences together, horizontally.
So, in a vertical sort of a way, we can hunt through a piece of writing looking for prepositions. We pull them out (vertically) and think (perhaps) about what might happen if we replaced them:
'I'm running to the shops.'
'I'm running from the shops.'
All day long we use prepositions like: to, from, with, at, by, in, on etc.
and preposition phrases like back from, on to, off of etc.
And please remember, I am citing all these out of context. In English, we very frequently make the same word do different jobs in different contexts.
The way we use these words as prepositions is often in adjectival and adverbial phrases.
'I am going to the doctors'. Because 'to the doctors' seems to be talking about 'am going', rather than 'I' we say that is adverbial. Because it doesn't have a finite verb in it, some would say it's a 'phrase' and not a 'clause'. Adverbial phrase.
Around the verb 'to be' (am, is, are/was, were/etc) we use a lot of phrases using prepositions:
'I'm in the bath.'
'He's not back from the shops.'
These appear to be describing the 'I' and the 'he' so they are adjectival.
You remember the adverbs called 'sentence adverbs'? eg 'Eventually, the plane landed.' Well, if adverbial phrases can act as sentence adverbs we ought to be able to birdspot prepositions there too:
'By all means, go.'
'In the circumstances, you could do that.'
So far, fairly straightforward.
But English (and all languages, in truth) are more complicated than that. One of the ways this complication business shows itself is in they way we construct verbs. As English developed, our ancestors wanted the action of verbs to express things like direction and place - and many metaphorical uses too - and they invented (and we go on inventing) 'phrasal verbs'. We construct these by taking a main verb like 'get' (and this is one of our favourites for doing this) and add words which in other circumstances we might call a preposition. What is extremely hard for children (well, anyone actually) being asked to spot prepositions in adjectival and adverbial phrases, is to distinguish that usage from the one in a 'phrasal verb'.
For a bit of fun, see how many different ways you can use the verbs 'get', 'take', 'go' by adding words that look like prepositions. What you're trying to do is make brand new verbs not simply using 'get', 'take' and 'go' in their core ways, like this:
'Being in London, really got him down.'
'It was difficult, but he took it in.'
'I don't go in for that sort of thing.'
These kinds of expressions, 'get...down', 'take...in', 'go in for' are a crucial part of how we construct the way we want to talk and write. Describing them grammatically is another matter altogether.
The reason why I'm raising it now is because
a) we sometimes ask children to spot prepositions but words like 'down', 'in', 'off' are very useful to us for attaching to verbs to make new verbs. In these situations many linguists would say they are not being prepositions.
b) in circumstances like these grammar is not easy and grammarians themselves differ over how to name and explain what's going on.
Most native speakers of English have no trouble using these expressions.
I asked him over and over again to put the picture up. He did in the end. I put the picture on the table for him.
What did he put the picture up with?
He put it up with a nail.
He put up with that, did he?
You asking him to put the picture up.
Yes, he did.
One core verb: 'put'
One phrasal verb: 'put up'
Another phrasal verb: 'put up with'.
Now, at this point I'm going to chicken out.
If you want to get a glimpse of how a very reasonable text book handles the grammatical description of this whole area, take a look at this:
Notice how, wikipedia's contributors aren't afraid to say how complicated it is, how inconsistent the descriptions can be and how grammarians differ in their terminology.
If only, people who tell us what we should tell children would be as flexible and open-minded.