AS - Conjuction or preposition

[cesar.rodriguez.blanco]

In the page 161 of the 3rd Edition of SC MGMAT, I do not understand the following example. AS can be a conjuction or a preposition.
Comparison AS (conjunction): You should walk AS she wants you to.
Equation AS (preposition): I think of you as my friend.

Futhermore, the guide says: AS does not mean "similar to" and then give the following examples:
I will jump up like a clown
I will jump up as a clown

Can any instructor exaplain the concepts? Could you give another examples?

Thanks.

[JonathanSchneider]

So, the important thing to note here is that "as" has multiple roles. One of these roles is to compare clauses. In this role, we often have the word "as" split against the word "like," which means "similar to."

The word "as" has other uses, however. One of these is to signify "while / at the same time as." For example: "As I was mowing the lawn, a Frisbee sailed into the yard." Here the word "as" just means "while." You can check out a list of other uses of "as" here: http://en.wiktionary.org/wiki/as#Adverb

As for the clown sentences, in the second the word "as" means "in the role of," which in this case means "dressed as," etc.

[cesar.rodriguez.blanco]

Thanks!!

[esledge]

On behalf of Jonathan: You are welcome!

[rx_11]

Dear MGMAT instructors,

I don't quite understand the use of "as" in this sentense:" You should walk AS she wants you to."

The usage of the "as" in this sentense is a "Comparison As". However, I think the two parts that is comparing are not parallel: "You should walk" does not compare with "she wants you to". So are there some omissions or something? But I can't find which part is missing. Can you throw more light on it?

Thanks very much!

[dmitryknowsbest]

In this case, "as" is used to mean "in the way that." So the whole sentence means "You should walk in the way that she wants you to [walk]."

Another example:
Since I am unemployed, I can spend my days as I wish.

This construction can be used even in sentences where you could not insert "in the way that":

You should do as he says.

Here, we would not say "do in the way that," but this is a peculiarity of the verb. If we said "You should act in the way that he specifies," the meaning would be the same.