Understanding prepositional phrasal verbs
Phrasal verbs are verbs of more than one word, usually two words, but sometimes even three. Everyone knows a few phrasal verbs: come in, go up, pick up, etc. The ones that most people know are the commonest ones. Native English speakers often use a much wider range of them. In general, however, they're used to define a more specific action than the single verb itself: come vs. come in, or go vs go away. Phrasal verbs are quite common in spoken English and less frequent in formal correspondance. You can also refer to phrasal verbs as multi-word verbs.
Look [verb] + for [preposition]: "I'm looking for my pen. Have you seen it?"
Because "for" is a preposition, a word that goes before nouns, pronouns and other substantives, we cannot say "I'm looking my pen for." The right order has to be "for + my pen"... or... preposition before its substantive.
Here's another example of a "[verb] + [preposition] = phrasal verb" formula: Be concerned [verb] + about [preposition]. "They're concerned about their future."
Because the particle, about, is a preposition, the noun or pronoun must follow it and not precede it. In other words, we can't say "They're concerned their future about."
Have a good week. Next week we will consider the [verb] + [adverb] = phrasal verb formula.