Some particles can be separated from the verb so that a noun and pronoun can be inserted, and some particles
can't be separated from the verb. In addition, some phrases are intransitive, meaning they cannot take a direct
object.
Separable
add up (meaning: to
add)
Correct: She added up the total on her calculator.
Correct: She
it
added
up on her calculator.
Inseparable get around (meaning:
to evade)
Correct: She always gets around the rules.
Incorrect: She always gets the rules around (This construction
makes no sense in English.)
catch on (meaning: Correct: After I explained the math problem, she began to
Intransitive to understand)
catch on.
Incorrect: She began to catch on the math problem.
(catch on
cannot take a direct object in this meaning.)
Correct: She began to catch on
the math problem. (the
to
word
to makes a
the math problem
n
indirect object, which is
acceptable in this meaning.)
Unfortunately, there is usually no indicator whether an idiomatic phrase is separable, inseparable, or
intransitive.
In most cases the phrases must simply be memorized. Below is a partial list of each kind of phrase.