Plead the text naturally. The original post can be found at https://dictionaryblog.cambridge.org/2020/01/29/let-down-and-look-after-the-difference-between-phrasal-verbs-and-prepositional-verbs/ I think It will be easier for you to read the post there. Thank you!
Let down and look after: the difference between phrasal verbs and prepositional verbs
By Liz Walter on January 29, 2020
My colleague Kate Woodford and I have written many posts about phrasal verbs because students find them difficult but know they need to learn them. These posts often include prepositional verbs, and readers sometimes ask about this.
So what is the difference between a phrasal verb and a prepositional verb? Strictly speaking, a phrasal verb consists of a verb and an adverb (or in the case of 3-word phrasal verbs, an adverb and a preposition). When phrasal verbs are transitive, the object can go either between the verb and the particle or after them:
+ She let her friends down.
+ She let down her friends.
Some phrasal verbs can also stand alone as intransitive verbs:
+ I enjoy chilling out with my friends.
On the other hand, a prepositional verb consists of a verb and a preposition which can never be split up and must always have an object:
+ I have to look after my little brother today.
So does this matter? Do we really need to know which are phrasal verbs and which are prepositional verbs? And should we teach them separately?
In my view, the essential point for learners is that with both types of verb you need to learn the verb and the particle together as one single unit of meaning. It is probably not worth worrying about whether “rely on” is a phrasal verb or a prepositional verb, especially if you just want to remember what it means.
Most of the major dictionaries for learners of English take this approach: both classic phrasal verbs and prepositional verbs are labelled ‘phrasal verb’. There seems to be general agreement that this is the most sensible way to present them.
However, if you want to use these words productively, you do need to remember that you can’t separate prepositional verbs. This is particularly important if you are using a pronoun as the object because in ‘real’ phrasal verbs, the pronoun “must” come between the verb and the particle:
+ She let them down.
However, as I mentioned above, prepositional verbs are never separated:
+ She looked after them.
Good dictionaries for learners give information about this in their entries, so if you are unsure, it is worth using one to check. For example, the Cambridge Dictionary says “look after sb/sth” to show that the object (‘sb’ for a person, ‘sth’ for a thing) must come after the particle, but “let sb down” to show that the object can separate the verb and the particle.
I’d be interested to know what you, as teachers and learners of English think: do you notice the difference between phrasal and prepositional verbs? Do you think it is necessary or useful to treat them differently? And do you have any tips for learning them?
Hi David. Thank you a lot!