"Please put the lamp on the desk."
"I think you're putting me on."

In the first sentence, on is a preposition showing the position of the lamp. In the second sentence, on is an adverbial particle. Put on is a phrasal verb meaning "fool" or "trick" in this sentence.

An important point is that a regular verb+preposition combination has two meanings. A phrasal verb, that is, a verb+particle, has a single meaning within a sentence. Many phrasal verbs have a number of different meanings in different situations. Yet the meaning of the verb+particle can usually be expressed with a single Latin-based verb.

Here are two sentences with the same meaning:

"They tore down the old building."
"They demolished the old building."

The verb tear has its own meaning, and so does the preposition down. They can combine with other words when they are alone. But as a phrasal verb, tear down, they have one meaning: "destroy."

In 1987, U.S. President Ronald Reagan visited West . He told a crowd in the divided city of Berlin, "Mr. Gorbachev, tear down this wall!"

Separable phrasal verbs

Now for the tricky part. You know that some verbs are transitive, which means they have a direct object. When such verbs appear as phrasal verbs, an object can either separate the phrase or follow it. Here’s an example.

"I decided to throw out my old jeans."
"I decided to throw my old jeans out."

Both of these sentences are correct. The object of the phrasal verb throw out is jeans. You can use a pronoun instead of jeans and ask,

"Are you sure you want to throw them out?"

However, you cannot ask, "Are you sure you want to throw out them?" Here, the pronoun them must appear between the verb and the particle.

Finding the frequent phrasal verbs

In recent years, language experts began to use computers to examine a large collection, or corpus, of written and spoken language. When researchers look for phrasal verbs, they find that many deal with an activity. They also find a few verbs combine with many particles. Among the most common verbs are come, put, get, go, pick, sit and take. These combine with the adverb particles up, out, in, on, off, and down to make up a group of very useful phrasal verbs.

Now, let’s look at transitive phrasal verbs. See the list at the end of the article. The verb get is part of many phrasal verbs. For example, we use get up to mean "to wake oneself up" or "to awaken someone." For example:

"My son loves to sleep late. I got him up on time to catch the bus this morning."

, the pronoun has to come between the verb and the adverb, so we cannot say, "I got up him."