A phrasal verb has two parts – a verb and a particle.
The particle is either a preposition or an adverb.
So with the phrasal verb ‘put on’ – put is the verb and on is the particle.
- When we can separate the verb and the particle.
- When we can’t separate the verb and the particle.
- When we must separate the verb and the particle.
To understand this we can put phrasal verbs into three groups.
1. No object
These have no object, for example, go away, come back, call back, take off (plane).
With this group the verb and the particle can not be separated. ‘I went him away’ is wrong. ‘He went away or I went away’.
2. With an object – cannot be separated
These have an object, for example, look after someone, look for something/someone, look forward to something, ask for something/someone.
Phrasal verbs in this group also can’t be separated.
‘I asked a drink for’ is wrong, ‘I asked for a drink’ is correct.
3. With an object – can be separated
These have an object but can be separated. – turn on/off, throw away, pick up, swith on/off, give up (smth)
For example ‘turn off the TV’. ‘Turn the TV off’. ‘Throw away the rubbish’. ‘Throw the rubbish away.
What we need to remember with this group is, if the object is a pronoun, it must go between the verb and the particle. We must separate them if the object is a pronoun. For example we cannot say ‘please pick up me from the station.’ We must say ‘Please pick me up from the station.’
‘Turn off it’ is wrong, we should say ‘turn it off’.
Another thing to remember is that phrasal verbs can have two or more meanings, and different meanings of the same phrasal verb might be in different groups.
For example, ‘the plane took off’ is group one, but ‘I took off my shirt’ is group three, (we can say ‘I took my shirt off’.)
So in order to avoid mistakes, I recommend learning what group phrasal verbs belong to when you learn their meaning.
Firstly you can think about if the verb has an object. If not then the verb and particle can never be separated. If the verb does have an object then a good dictionary will show you if the verb and particle can be separated or not. For example give up will be shown, give up sth, give up (sth)’ give (sth) up, (sth = something) this shows that give up can be used without an object, ‘I give up…’ (cannot separate verb and particle) or with an object, ‘I gave up smoking/I gave smoking up’ (verb and particle can be separated).