Source: answer explanation for Housing Market SC question from my CATs

When comparing clauses (i.e., a phrase containing a subject and a verb), we must use "as" instead of "like."
For example,
"She sings like her mother"
and
"She sings as her mother does"
are both correct, but
"She sings like her mother does"
is not.

I agree that the second one is correct, while the 3rd is not.

But I feel the first sentence is wrong= "She sings like her mother"
We are comparing her singing to her mother.
"She sings" is a clause, isn't it?

I agree that the first sentence is problematic. You can, however, write the same information using "like" or "as" just depending on how you construct the sentence.

Try this instead: Susan, like her mother, is a good singer.

Or:
Joe, like Mary, has a cat.
Joe has a cat, as does Mary.

Both of the above are correct - I just have to write the sentence differently.
I can't say: Joe has a cat, like Mary. I have to put Mary over near Joe if I want to use "like."

You can say "Joan sings like her mother," meaning, "Joan sings in the same way as her mother does." Don't let yourself get trapped by the semantic argument too much: "am I comparing Joan's mother with Joan, or am I comparing the way Joan's mother SINGS with the way Joan sings?" In fact, you're arguably doing more of the latter, but just as Stacey says, you can often construct the sentence EITHER with "like" OR with "as." The bigger issue is structural: first of all, never put a tensed verb after "like." For instance, never say "Joan sings like her mother sings." Secondly, if you use "like," try to put it as close as possible to the noun you're doing the comparison with, so that you avoid ambiguity ("Joe has a cat like Mary."). This second point leads you to put "like" constructions near the front of sentences on the GMAT, since you're often doing a comparison with the subject.

Incidentally, there IS a meaning difference between "Like her mother, Joan sings" and "Joan sings like her mother." In the first case, what you're saying is that Joan engages in the same activity (singing) as her mother. In the second case, you're saying that Joan engages in that activity IN THE SAME WAY as her mother does. However, to my knowledge, the GMAT hasn't tested this distinction -- both forms are correct, after all (they just mean slightly different things).

Thanks for the clarification.

Your response says "The bigger issue is structural: first of all, never put a tensed verb after "like." ".

Then why is "People like you inspire me" correct? "Inspire" is a verb here. Please clarify.

because it's not part of the same construction. that construction is

(people like you) (inspire me)
i.e., (noun phrase) (verb)
...so the 'inspire' is TOTALLY independent of the 'like' construction.

in the faulty constructions quoted by chris above, the verb is actually the latter part of the 'like' construction. do you see the difference?

People like you always inspire me.
The verb "inspire" is used for "people" and not "you".
To understand the sentence better-let us take help of commas (though that will make an essential modifier anon-essential one).
People,like you,always inspire me.

Now consider the sentence:
People,like you are,always inspire me.
Here we should use as and not like.

I must leap to Ron's defense, Parveen! He is right.

When looking at Like/As splits, I count the verbs. A sure sign that there is a noun comparison requiring "like" is the presence of only one verb...the compared nouns will "share" that one verb. "As" comparisons require each clause to have a verb, so there must be two verbs...but those verbs need to match somewhat.

"People like you inspire me." This sentence could be split into two: "People inspire me." and "You inspire me." "People" and "you" are alike; they both share subject status for the verb "inspire."

Let's look at your suggestion for a way to use As: "People, as you are, inspire me."

(A) This has two verbs, which makes this a comparison of clauses: "you are" and "people inspire." That's good.

(B) However, the verbs themselves are not a good match. Here are some suggested changes.

(B1) "you are" would nicely match "people are," for example:
"You are an inspiration to me, as are other people." or
"You are an inspiration to me, as my mother was."
Both verbs of being!

(B2) "you inspire" would nicely match "people do (inspire)," for example:
"You inspire me, as other people do."
Both are the verb "inspire" ("do" is called a proform, it's like a verb pronoun--it means "inspire" in this context).

(C) Generally, "like" phrases work well at the beginning of a sentence or right after the noun they modify, while "as" phrases work well at the end of a sentence. Your placement of the As comparison clause right after a noun (the subject no less! and separating it from its verb!) is not ideal.

@ Stacy: Why dont you publish a book with all these tit-bits! It would save us so much time!

More than thirty years ago Dr. Barbara McClintock, the Nobel Prize winner, reported that genes can
"jump," like pearls moving mysteriously from one necklace to another

is this correct? if yes how can we reconstruct the sentence using "as"...

In above sentence, "like pearls moving..."
I think moving is participle, so acts as adjective to pearls
like is correct for this sentence..

To use as, this might work ..

More than thirty years ago Dr. Barbara McClintock, the Nobel Prize winner, reported that genes can
"jump," as pearls move mysteriously from one necklace to another

I'm not saying this is correct, just asking?