Which of these sentence is not correct?

[tedtmc]

Do you study as hard as your friends do?
Do you study as hard as them?
Do you study as hard as they?

Which is not correct and why?

 

[Abstract Idea]

Do you study as hard as your friends do?
Do you study as hard as them?
Do you study as hard as they?

Which is not correct and why?

The second one is not correct, as suggested by the other ones:

Do you study as hard as your friends do? (correct)
Do you study as hard as they do? (correct)
*Do you study as hard as them do? (wrong)
Do you study as hard as they? (correct)
("they" is a subjective pronoun while "them" is an object pronoun)

It is related to something called "parallelism" or something like that in grammar.


PS Not a native speaker

 

[MASM]

The second one is not correct, as suggested by the other ones:

Do you study as hard as your friends do? (correct)
Do you study as hard as they do? (correct)
*Do you study as hard as them do? (wrong)
Do you study as hard as they? (correct)
("they" is a subjective pronoun while "them" is an object pronoun)

It is related to something called "parallelism" or something like that in grammar.


PS Not a native speaker

I have read in a book that you can use in informal style object pronouns, so I think the sentence Do you study as hard as them? would be correct. like in : She doesn't sing as well as me

However, Do you study as hard as they? for me, would need the structure subject+ verb so it would be Do you study as hard as they do? as in: She doesn't sing as well as I do

 

[mmasny]

However, Do you study as hard as they? for me, would need the structure subject+ verb so it would be Do you study as hard as they do? as in: She doesn't sing as well as I do

I think 'as they' is correct without the verb. And I suppose some prescriptive guys would call it better grammar than 'as them'.
PS: I'll try to get some links if needed.

 

[MASM]

I think 'as they' is correct without the verb. And I suppose some prescriptive guys would call it better grammar than 'as them'.
PS: I'll try to get some links if needed.

Well, that is not my opinion this time It's Mr Swan's:

I quote:
" Pronouns after as"
"In an informal style we can use object pronouns (me, him etc) after as.
She doesn't sing as well as me

In a formal style, we prefer subject + verb after as
She doesn't sing as well as I do
A subject form without a verb (as well as he) is unusual in this structure in modern English."

 

[mmasny]

Well, that is not my opinion this time It's Mr Swan's:

I quote:
" Pronouns after as"
"In an informal style we can use object pronouns (me, him etc) after as.
She doesn't sing as well as me

In a formal style, we prefer subject + verb after as
She doesn't sing as well as I do
A subject form without a verb (as well as he) is unusual in this structure in modern English."

And I must agree with Mr Swan It's certainly unusual, but I heard people say this is the only correct.

 

[kfredson]

Do you study as hard as your friends do?
Do you study as hard as them?
Do you study as hard as they?

Which is not correct and why?

The correct sentences are, as has been said, the first and third ones. In practice, people (at least in AmE) seem more likely to use "do" with the third version than with the first. And, yes, increasingly you are hearing it said with "them" at the end. This is certainly colloquial, however, and sounds wrong to my critical ears.

 

[kfredson]

Do you study as hard as your friends do?
Do you study as hard as them?
Do you study as hard as they?

Which is not correct and why?

Now that I think about it, when comparing two things most people don't end a sentence with a pronoun in the nominative case without adding a word. For some reason it doesn't seem to sound right. We know that it is proper English but it sounds to many as though it is a bit stilted.

Do you study as hard as I do?
Do you think they are as smart as I am?
Do they run as fast as we do?
Is your daughter as cute as she is?

Yes, you could drop off the verb, but in my practice most people don't. On the other hand, when in common parlance we end the sentence incorrectly with the accusative pronoun, we would never add the verb. (Your second sentence is an example.)

 

[Eric Davis]

Do you study as hard as your friends do?
Do you study as hard as them?
Do you study as hard as they?

Which is not correct and why?

I'm not a teacher...


They look as though they are elliptical sentences:

Do you study as hard as your friends [study].
Do you study as hard as they [study].

I believe that the second sentence that ends with them is incorrect because the pronoun is in the objective case when it should be in the subjective case--the nominative of study.