Some phrasal verbs can be separated with an object, for example 'switch on the light' can also be 'switch the light on'.
Not all phrasal verbs can be separated, so it's a matter of memorising which ones can and which ones can't.
Here's a little exercise to help you along. Complete the sentences by choosing the correct option. Remember to put the verb in the correct tense.
Lesson by Seb @ EC Cape Town English School
Link: The position of Phrasal Verbs
Link: 10 Common Phrasal Verbs