Is the following explanation enough to find out the difference between a preposition and adverb used in a phrasal verb.. If not, then please can you give another alternative.

Many of the words in the preposition list can also be used as adverbs. The problem for you is to figure out when a word from the list is being used as an adverb or as a preposition. When in doubt, ask the questions whom or what after the word. If there is a noun or a pronoun to answer the question, then the word is a preposition with an object--a prepositional phrase. If there is not a noun or pronoun to answer whom or what, then the word you are worried about is an adverb.

Example: The girl looked over and then ran down the street.

Both the words "over" and "down" are on the preposition list. Say the word "over" and add "over what?" There is no what or whom word after "over." Now say "down what?" -- "down the street." There is a noun "street" which tells what after the word "down." Therefore, "down" must be a preposition with the prepositional phrase being "down the street."


( http://www.readbygrade3.com/prep.html )

These rules work for all those sentences that contains a preposition. See the following sentence;

Here (in the 1st sentence) on is a preposition and answers the question what.
1. I hadn't reckoned on being the center of attention. ( on what? on being the center of attention.)
We abided by the rules.
He accounted for the discrepancy.
They asked for an extension.
We are banking on good weather tomorrow.
Please bear with the delay.

But they doesn't work for this one;

Here on is not a preposition but an adverb and still answers the question what.
2. He kept on changing the subject. (on what? on changing the subject.)

GB
Full Member450
If I am not sure whether it is a verb phrase or a verb plus a preposition, I create a question.

I ran up the hill.
where did I run? up the hill. this is not a pv becoz you do not need the particle for the question to make sense.
---------------------
I ran up a huge telephone bill.

What did I run up? A huge telephone bill.

what did I run? no. makes no sense here.
Senior Member2,552
Anonymous:
What did I run up? A huge telephone bill/

But you didn't literally run UP it, did you? You're probably much larger physically than the telephone bill, however large the amount of money you owe is.

I'm just teasing you. The reason that "up" in that sentence is an adverb is because it changes the meaning of the verb. It's now a phrasal verb, whereas in "I ran up the hill," "ran" literally means running and "up" is the direction I'm running. "Up" doesn't change the meaning of "ran," it adds more information about the direction.
Just in case you didn't realize it, I thought I'd mention that you just answered a question that was asked more than three years ago, and the person who asked the question is probably not still waiting for an answer. Emotion: smile

It's a good idea to check the dates on posts.

CJ
Veteran Member51,799
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Anonymous:
if "after" is followed by gerund then is it an adverb or a preposition?
Anonymous:
Wrong! CalifJim. The person who asked the question is not necessarily the only person who waits for this very answer. It has been useful to me, NOW. Check my post's date. Emotion: smile
Anonymous:
Just in case you didn't realize it, I thought I'd mention that you just answered a question that was asked more than three years ago, and the person who asked the question is probably not still waiting for an answer

True! But here is in ANOTHER YEAR later and I'm looking at the answer. The beauty of the web...
Anonymous But here is in ANOTHER YEAR later and I'm looking at the answer. The beauty of the web...
There you go. It's always something! Emotion: smile

If you want more on this topic, see Differ between a preposition and an adverb in a phrasal verb..

CJ
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