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Separable vs inseparable phrasal verbs

Some phrasal verbs can split around their object — turn the light off — while others can never split. Getting this right is the difference between sounding native and sounding like a textbook. The rule is simple once you know which structure you're dealing with.

What separability means

A phrasal verb is separable if its particle can sit on either side of the object:

✓ She turned off the light.
✓ She turned the light off.

A phrasal verb is inseparable if its particle must always sit with the verb, with the object coming after:

✓ She looked after the kids.
✗ She looked the kids after.

The structural rule

Separability tracks the grammatical type of the particle:

StructureSeparable?Examples
Verb + adverb (transitive)Usually yesturn on, pick up, put off
Verb + adverb (intransitive)N/A (no object)get up, break down, show up
Verb + prepositionNeverlook at, depend on, look after
Verb + adverb + prepositionNeverput up with, come up with, look forward to

The complication: the same two words can be either an adverb (separable) or a preposition (inseparable) depending on the phrase. Turn off (off is adverb) separates; look after (after is preposition here) doesn’t. That’s why looking at each phrase individually, rather than trusting the particle, is safer.

The pronoun rule (most important)

With separable phrasal verbs, a pronoun object must go between the verb and the particle. This is the highest-yield rule in the whole topic — getting it wrong is immediately audible to a native speaker.

With a noun object — either order:

✓ I picked up the book. / I picked the book up.

With a pronoun object — must separate:

✓ I picked it up.
✗ I picked up it.

This applies to every separable phrasal verb with a pronoun: turn it off, throw it away, take them off, call him up. The pronoun always goes inside.

A three-step test for any phrasal verb

  1. Does it take an object at all? If no, separability doesn’t apply (get up, show up). Just use the phrasal verb as-is.
  2. Is it a three-word phrasal verb? If yes, it’s inseparable. Object always goes after the last particle (put up with the noise, look forward to seeing you).
  3. Replace the object with a pronoun and try both orders. If “verb pronoun particle” sounds right (turn it off), it’s separable. If “verb particle pronoun” sounds right (look after it), it’s inseparable.

Or just check the separability badge on any Phrasalyze entry — every phrasal verb is tagged.

Twenty common separable phrasal verbs

Drill these first — they cover a huge share of transitive phrasal-verb usage:

turn on, turn off, pick up, put off, put on, take off, throw away, call up, fill out, find out, give up, hand in, look up, set up, take over, work out, write down, wake up, bring up, figure out.

Ten common inseparable phrasal verbs

These never split — object always goes after the full phrasal verb:

look after, look at, depend on, wait for, run into, come across, put up with, come up with, look forward to, get on with.

Frequently asked questions

Is there a rule for knowing if a phrasal verb is separable?
There's a reliable heuristic: transitive verb + adverb combinations are usually separable (turn the light off / turn off the light). Verb + preposition combinations are always inseparable (look at the sky, never look the sky at). Three-word phrasal verbs (put up with, come up with) are always inseparable. But there are exceptions, so when in doubt, check Phrasalyze's separability badge on each entry.
What happens if I use the wrong word order?
Native speakers will still understand you, but the mistake flags non-native production. With a pronoun object it can sound seriously wrong — *I turned off it* is ungrammatical; you must say *I turned it off*. Inseparable phrasal verbs used separably sound equally awkward — *I look the stars at* is not interpretable.
Why is it "turn it off" but "look at it"?
Because turn off is a verb-adverb combination where the adverb (off) modifies the verb's action; pronouns have to slot between them. Look at is a verb-preposition combination where the preposition introduces its object — the object belongs to the preposition and can't separate it from the verb. The two structures look similar but behave very differently.
Are any phrasal verbs obligatorily separated?
Yes, in one case: when the object is a pronoun, most separable phrasal verbs require separation. "Pick up the pen" and "pick the pen up" are both fine, but "pick it up" is mandatory — "pick up it" is wrong. This is the single most-tested separability rule in English exams.
Do inseparable phrasal verbs ever accept a pronoun between verb and particle?
No. Inseparable means the verb and particle never split, for any object. "Look after the kids" stays "look after them" — never "look them after." This is consistent across all inseparable phrasal verbs.

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