SC-Green Bloom

[shimashouri]

Aerugo, also known as verdigris, is the green "bloom" visible on many copper items, and is produced, like iron rust, over the course of time by the exposure of the metal to the oxygen in the atmosphere.

A)visible on many copper items, and is produced
B)that is visible on many copper items, and which produces
C)visible on many copper items, and produces
D)that is visible on many copper items, and that produces
E)which is visible on many copper items, and which is produced

The answer is A in manhattan CAT Gmat.
But I have a question regarding Answer A. In SC strategy guid book of manhattan, page 190, it writes that " Do not use comma before and to seprate two verbs that have same subject."
In here, answer A has 2 verbs with one subjects. So, I choose answer E.
Could you explain more? and why answer E is wrong?

Thanks in advance

[mschwrtz]

In SC strategy guid book of manhattan, page 190, it writes that " Do not use comma before and to seprate two verbs that have same subject."

That's a good general rule about commas, but there are exceptions. In fact, just a few days ago I fielded a question on our GMAT Prep forum about an SC question very much like this one.

Standard usage permits a comma here because the first of the two parallel verbs introduces a pretty complicated clause, is the green "bloom" visible on many copper items, whose noun, items, might otherwise seem to be the first of the elements coordinated by and. The comma makes it clear that something earlier in the sentence must be parallel, and when we see that a verb follows and it's not hard to see what that first element is.

I'm not sure that this sentence would be hard to follow without the comma, so I'm noy sure that it's required, but it is permissible.

and why answer E is wrong?

Consier the sentence that would result:

Aerugo, also known as verdigris, is the green "bloom" which is visible on many copper items, and which is produced, like iron rust, over the course of time by the exposure of the metal to the oxygen in the atmosphere.

In this sentence the modifiers which is visible... and which is produced... are parallel. This changes the meaning of the original sentence, in which the verbs is the... "bloom" and is produced are parallel.

[chitrangada.maitra]

Hi,

I could not really understand how option E changes the meaning of the sentence.

Option A: Aerugo, also known as verdigris, is the green "bloom" visible on many copper items, and is produced, like iron rust,...

Option E: Aerugo, also known as verdigris, is the green "bloom" which is visible on many copper items, and which is produced, like iron rust,.....

Please let me know how they differ in meaning.

Thanks,

[jnelson0612]

Hi,

I could not really understand how option E changes the meaning of the sentence.

Option A: Aerugo, also known as verdigris, is the green "bloom" visible on many copper items, and is produced, like iron rust,...

Option E: Aerugo, also known as verdigris, is the green "bloom" which is visible on many copper items, and which is produced, like iron rust,.....

Please let me know how they differ in meaning.

Thanks,

Read Michael's excellent explanation again and then let's check out what's going on here. In A, the parallelism is with "bloom" and "is produced", both describing Aerugo.

In E, the parallelism is "which is visible" and "which is produced", both describing "bloom".

It's a subtle distinction and quite hard to spot!

[rikky.bora]

Sorry for bumping up an old thread. But, just wondering whether we can eliminate E based on the fact that it contains 2 "which phrases" - nonessential modifiers : two non-essential modifiers when removed from the whole sentence leave no real meaning to the sentence as a whole.

[jnelson0612]

Sorry for bumping up an old thread. But, just wondering whether we can eliminate E based on the fact that it contains 2 "which phrases" - nonessential modifiers : two non-essential modifiers when removed from the whole sentence leave no real meaning to the sentence as a whole.

Not so sure on that. Using your suggestion, we could have:
"Aerugo, also known as verdigris, is (a) green bloom".

I think Michael's explanation is a more sound reason for eliminating E.

[rikky.bora]

Sorry for bumping up an old thread. But, just wondering whether we can eliminate E based on the fact that it contains 2 "which phrases" - nonessential modifiers : two non-essential modifiers when removed from the whole sentence leave no real meaning to the sentence as a whole.

Not so sure on that. Using your suggestion, we could have:
"Aerugo, also known as verdigris, is (a) green bloom".

Nope, the non-underlined part of the given SC Question reads
"Aerugo, also known as verdigris, is the green bloom",

[messi10]

Hi Ricky,

I agree with Jamie's post.

Also, note that the first which is not a non-essential modifier. A non - essential modifier has to be preceded by a comma and that is not the case with option E.

If you read the SC guide on page 89, you will see that which vs that is no longer used to decide whether the modifier is essential or non essential. It is the combination of comma and which/that that makes the distinction.

Regards

Sunil

[rikky.bora]

Hi Ricky,

I agree with Jamie's post.

Also, note that the first which is not a non-essential modifier. A non - essential modifier has to be preceded by a comma and that is not the case with option E.

If you read the SC guide on page 89, you will see that which vs that is no longer used to decide whether the modifier is essential or non essential. It is the combination of comma and which/that that makes the distinction.

Regards

Sunil

Hey Sunil,

Good catch !! Thank you for another nifty tip :)

[jnelson0612]

Thanks Sunil!

[I_need_a_700plus]

Can someone explain why passive is better than active in this sentence correction?

Many thanks.

[jlucero]

Because the subject is "Aerugo":

Aerugo (1) is visible on many copper items, and (2) is produced over the course of time.

You can't say:

Aerugo (1) is visible on many copper items, and (2) produces (produces what? itself?) over the course of time.