Separable
When phrasal verbs are transitive (that is, they have a direct object), we can usually separate the two parts. For example, "look up" is a separable phrasal verb. We can say: "look up the word" or "look the word up".
However, if the direct object is a pronoun, we have no choice. We must separate the phrasal verb and insert the pronoun between the two parts:
Look up the word.
Look the word up.
Look it up. (It's incorrect to say: Look up it).
Inseparable:
However, if phrasal verbs are intransitive (that is, they don't have a direct object), we can't separate them.
Ex: I want my marks to go up.
Sometimes it's not easy to know whether they are separable or inseparable. If you are not sure, use a noun (or noun phrase) and don't separate the phrasal verb. You'll be always right that way! ;)
Here you have a website where you can look up the definition of the phrasal verbs, as well as the type (separable or inseparable)
