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I read a grammar book. In the chapter on phrasal verb, it says that if the object is a pronoun that should be put between the (transitive) verb and the adverb. I believed that is also true for such objects as something, anything, this, that, etc. and that the sentence like "Pick up this" wouldn't be grammatical.
But.. I saw this today on Wikipedia(href="http://en.wikipedia.org/wiki/Determiner (linguistics)" style="cursor: pointer; color: rgb(58, 88, 151); text-decoration: none; ">http://en.wikipedia.org/wiki/Determiner_(linguistics ) ):
In phrasal verbs, pronouns must appear between the verb and particle. Determiners may occur after the particle.
  1. pick it up
  2. *pick up it
  3. pick this up
  4. pick up this
I don't understand how 'pick up this', not 'pick this up', could be correct. If 'this' in 'pick up this' is a determiner, a noun sholud be followed, shouldn't it? Hmm... Is a noun left off there? =/
If "pick up this" stands alone, please tell me how it could be.
Comments  
Although many phrasal verbs can take an object in both places, you must put the object between the verb and the preposition if the object is a pronoun.
So you are correct and wikipedia is wrong.
Well done!
I'm quite proud that I sussed that out.