* leaching, the recovery of copper

[RonPurewal]

And，regarding Choice E，"well established..." is used as an non-essential modifier of "a method", thus implying that there is only one method of mineral extraction all along? I can't tell from the original prompt whether leaching is the only one method there. So I think the use of non-essential modifier here is not a big deal. Please comment on my thought.

Thanks in advance.

This difference ("essential" / "nonessential") has NEVER been tested by GMAC. Never ever ever.
To test this difference would bias the test against speakers of some languages, especially Eastern European languages, which often use this kind of punctuation in different"”even opposite"”ways.

Still, choice E is nonsense. Look at what happens when you remove the modifier:
"XXX had been a method, but people didn't realize yyy until 25 years ago."
No longer a contrast.
The contrast exists between that knowledge the fact that the method was well-established earlier. Not the existence of the method itself.

[Haibara]

Thanks Ron, for all your great explanations and patience.

[RonPurewal]

You're welcome.

[FanPurewal]

what's wrong with A?
it is not fragment right?

and i think the structure of A is ok:
as noun., SUBJECT VERB OBJECT, but SUBJECT VERB OBJECT.

can someone clarify it?
thanks a lot

[RonPurewal]

If you remove modifiers from A, it has two subjects. (It's like "My brother, he lives in Texas.") Not workable.

[LaraZ595]

Why is it correct to say that "sth. is as early as the eighteenth century" I feel that it should be "sth is established as early as the eighteenth century"….a verb feels necessary…some one explain please?

Also, Ron, is there a summary of all modifiers and what they modify? Am I right in understanding them as follows?

, which (normally modify the noun right before it, unless there are disagreements on plural singular etc.)
which (modify the noun right before it, the only difference between which and ,which is that one is essential and the other is non-essential, so the difference is more contextual in a way)
, Verb+ed (I've no idea, the noun right before maybe?)

if it is "a method of mineral extraction, well established in the 18th century", is "well established" modifying "mineral extraction" or "a method"?

Thanks!

[RonPurewal]

Why is it correct to say that "sth. is as early as the eighteenth century" I feel that it should be "sth is established as early as the eighteenth century"….a verb feels necessary…some one explain please?

you're right that a verb is necessary; you're just dividing up the sentence incorrectly.

"as early as xxxx time" modifies the observation "yyy was a well-established method".
the verb you're seeking is "was".

[RonPurewal]

, which (normally modify the noun right before it, unless there are disagreements on plural singular etc.)

basically yes.
can also modify "noun1 + preposition + noun2" (e.g., OG13 #29). (in all such instances that GMAC has published, noun2 fails to agree with "which".)

which (modify the noun right before it, the only difference between which and ,which is that one is essential and the other is

you will NEVER see "which" without a comma on this exam.

[RonPurewal]

, Verb+ed (I've no idea, the noun right before maybe?)

this one could describe either the preceding noun (e.g., OG13 #35) or the entire action (e.g., Maria collapsed on the couch, exhausted from a long day's work). just use context as your guide.

f it is "a method of mineral extraction, well established in the 18th century", is "well established" modifying "mineral extraction" or "a method"?

Thanks!

this is a non-question, for the reason explained above.

[Navneet]

Hi Ron

1. As you said earlier in this thread that "as early/late as" are not used for comparison, but do "as soon as" is used for comparison? (Are there any other time comparison tools ?)

2. What role do "as early as" play - You said that " they are ways of placing boundaries on the date of some event" but I have some examples in which I think similar role could be played by other,shorter, words.

a. Teachers have said the Principle could announce a series of disciplinary actions as early as this week. ( or it could be "by" this week) why we are using as early as here ?

b. Mars news media speculated that new elections could be held as early as next March. ( or it could be "by/at" next march) why we are using as early as here ?

c. A Christian council was held at Edessa as early as 197. ( or it could be "at" 197) why we are using as early as here ?

d. The history of the automobile typically begins as early as 1769. ( or it could be "at" 1769) so why we are using as early as here ?

Please clarify

[RonPurewal]

Hi Ron

1. As you said earlier in this thread that "as early/late as" are not used for comparison, but do "as soon as" is used for comparison? (Are there any other time comparison tools ?)

any of these can be used in a comparison (e.g., i don't wake up as early as my brother does). however, they can also be used to set boundaries, as in the example at hand here.

if these constructions are used to set a boundary, two aspects are important:
1/ we should be talking about something that's earlier than expected/normal;
2/ technically, "as early as X" = "at X or later". ("by X", by contrast, means "at X or possibly earlier".)

e.g.,
we sometimes get snow as early as mid-october
––> 1/ this is unusually early (i.e., the listener/reader would not expect snow to come so early in the autumn)
––> 2/ the first snow might come in mid-october; it might come later. it definitely won't come earlier.

[RonPurewal]

a. Teachers have said the Principle could announce a series of disciplinary actions as early as this week. ( or it could be "by" this week) why we are using as early as here ?

different boundaries.
"... by the 30th" = on the 30th or before;
"... as early as the 30th" = on the 30th or later.

this particular example would not make sense with "by", because "this week" is already the current time; "...will happen by X" is only a sensible statement if X is in the future.
if that's the intended meaning (i.e., "this week at the latest"), then you'd just write "...could announce xxxx this week".)

[RonPurewal]

b. Mars news media speculated that new elections could be held as early as next March. ( or it could be "by/at" next march) why we are using as early as here ?

again, different meanings.

"by next march" = next march or earlier + no implication that this is unexpectedly early/late
"as early as next march" = next march or later + implies that this is unexpectedly/abnormally early

[RonPurewal]

there's also a third use of these forms: to place something at an exact time, but to emphasize the surprising nature of that time.

e.g.,
Vladimir could play Chopin's Scherzi as early as his 7th birthday
––> vladimir could play these pieces when he turned 7. here, the "as early as" functions mainly to emphasize "whoa, that's super young for someone to play such masterpieces".

[RonPurewal]

c. A Christian council was held at Edessa as early as 197. ( or it could be "at" 197) why we are using as early as here ?

• this could be a usage of the type described in the preceding post ("there was a council in 197, and WHOA that's super early").

• it could also be a boundary ("we don't know the exact date, but 197 is the earliest estimate; it could have been later than that").

without additional context, we can't tell which.