Rule #1: Wh- question Rule
The word in question is a preposition if it can be moved to the front of a wh- question. Here's an example:
I come from Atlanta.
We know "from" is a preposition because the following, though formal-sounding, is acceptable to our ears:
From
where do you come?
Here's what happens to the particle in a phrasal verb when we apply this rule:
She threw out the old newspapers.
This sentence becomes awkward and ungrammatical when we apply the wh- question rule
*Out
where did she throw the old newspapers?
Rule #2: Relative Clause Fronting Rule
The word in question is a preposition if it can be fronted in a relative clause. Another example:
They learned about water skiing.
"About" is a preposition because the following sentence is grammatically correct even though it sounds stodgy.
Water
skiing, about which they learned, is not as easy as it looks.
Let's look at what happens to the particle in a phrasal verb when we apply this rule:
I should hand in my paper early.
This sentence becomes awkward and ungrammatical when we apply the relative clause fronting rule:
*My
paper, in which I should hand early, is my last one this
term.
Rule #3: The Insert Adverb Rule
The phrase in question is a verb+preposition combination if an adverb can be inserted between the verb and the preposition. Here's an example:
My wife argued with the waiter.
"Argued with" is a verb+preposition combination because the following sentence is grammatically correct.
My
wife argued endlessly with the waiter.
Let's look at what happens to a phrasal verb when we apply this rule:
Can you pick up my friend from the airport?
Now, here's the ungrammatical sentence produced when we insert an adverb within the phrasal verb:
*Can
you pick quickly up my friend from the airport?
Of course, the rules governing the combination of verbs and prepositions are quite complex. Here are some good resources for learning more about this:
Pat
Byrd
Department of Applied Linguistics
& ESL
Georgia State University
Atlanta, GA 30302
patbyrd@gsu.edu
Telephone: 404-651-2934