In an um...zu... clause, the infinitive has to be at the end. But when using a separable verb, you 'separate' the prefix and the rest of the infinitive by inserting ...
"Turn off the TV" is an example of a phrasal verb, which is a verb that has a base verb and one or two particles. Credit: MikeSleigh/Getty Images A ‘phrasal verb’ is a verb that has a base ...