A phrasal verb is a verb combined with a preposition or adverb (or both) that means something different from each of the words that make up the verb. There are two types of phrasal verbs. Separable phrasal verbs can be broken up by other words, while inseparable phrasal verbs cannot be separated by other words.
Separable Phrasal Verbs
You can insert other words into the middle of a separable phrasal verb. Consider the following example, using the phrasal verb take back:
I need to take back the shirt I lent you.
Where’s that shirt I lent you? I need to take it back.
Inseparable Phrasal Verbs
Inseparable phrasal verbs can be transitive (i.e., they can take a direct object), but you can’t insert that direct object into the middle of the phrasal verb. In other words, they can’t be separated, thus their name. Consider the following examples:
If you focus your education solely on one area, you’ll have nothing to fall back on if you change your mind.
Each child should have at least one older child to look up to.
What does i.e. stand for? It stands for id est, or that is.
You can find the original post here.