Providing initial evidence that

[jingjiaol257]

ankur --
this may be a regional distinction -- perhaps english is structured differently in the country where you were educated -- but a single construction "twice of ..." would always be considered incorrect in american english.
the only way you're going to have "twice" next to "of" is when they're parts of completely different constructions; see #3 below.

basically, there are three different kinds of acceptable uses of "twice":
1) twice NOUN/PRONOUN, where the noun or pronoun describes a numerical quantity of something;
2) twice as ADV/ADJ (as)... / twice this/that ADV/ADJ
3) twice by itself, meaning that something has happened two times (e.g., i've been there twice).

#3 is the only one of these constructions in which you might see "twice" followed by "of" -- and then only if they're independent constructions.
for instance, you could say
smith has already been advised twice of the foolishness of these actions.
... notice that this construction is NOT "twice of"; the "of" is part of the boldfaced construction, but the "twice" is not.

note that, in #1, there may be possessives and/or adjectives in front of the NOUN.

--

your examples:

Usage : X is twice that Y

this isn't a construction.
you're only going to have "twice that..." in one of the following 2 cases:
1) "that" is a relative pronoun (e.g., the unemployment rate of Country X is twice that of Country Y)
2) they're part of independent constructions (e.g., smith has already been advised twice that these actions are foolish)

1)The total money i have is twice that you have.

incorrect -- this "that" is not a relative pronoun such as the one above.

2)The total money i have is twice of what you have.
3)the total money i have is twice of that you have.

both incorrect -- "twice of X" is never correct as a single construction.

4)the total money i have is twice as much as you have.

"twice as much as you have" is ok.
"total money" isn't, though; you'd have to say "the amount of money" or "the total amount of money".

5)the total money i have is double of what you have.

incorrect -- the correct construction is "double X", not "double of X".

6)The number of books i have are twice that you have.

incorrect, same reason as #1

also, note that "the number ... are ..." is incorrect in all of these sentences; "the number" is singular, so the verb should be "is".

7)The number of books i have are twice as many as you have.

"twice as many as ..." is a correct construction.
you can't say "the number is twice as many", though -- that's a redundant construction.
you'd just say "i have twice as many books as you have."

8)the number of books i have are twice of as many as you have

wrong. can't have "twice of X".

hi ron
i can understand all the explanation you gave except the first one.
1)The total money i have is twice that you have.

incorrect -- this "that" is not a relative pronoun such as the one above.

do you mean that in the sentence this "that" is a demonstrative pronoun instead of a relative pronoun that we need???
i really cannot find the difference of that between the correct answer this question and this sentence above:

Correct Answer:total amount of pollutant emitted annually by vehicles at O'Hare International Airport is twice (that emitted annually bu all) motor vehicles in Chicago metropolitan area.

The total money i have is twice that you have.

is the "that" in correct answer a relative pronoun?is the "that" in latter sentence a demonstrative pronoun??

Thanks!!

[RonPurewal]

"Twice that you have" doesn't work.

Consider the following examples, each of which could be the second half of a comparison:
...twice the amount that you have
...twice the quantity that you have
etc.

With "that" (= pronoun) in there, you'd need ...twice that that you have. That's absolutely unreadable, of course, so you'll never see it.

[jingjiaol257]

"Twice that you have" doesn't work.

Consider the following examples, each of which could be the second half of a comparison:
...twice the amount that you have
...twice the quantity that you have
etc.

With "that" (= pronoun) in there, you'd need ...twice that that you have. That's absolutely unreadable, of course, so you'll never see it.

hi ron
Thank you so much for your explanation.I get it.

[RUOYUNL702]

Ron,

In correct answer D, can we assume that the word "that" refers to pollutant emitted annually? or just pollutant?

I am often confused by what the word "that" really refers to when "that" is used to abbreviate a sentence.

this is parallelism.
just look at the parallel structures side-by-side, and notice which parts match up to which other parts.

i.e.
the total amount of pollutant emitted annually by vehicles at the O'hare International airport
is twice
that emitted annually by all...

hi,ron,if "that"refers to "the total amount of pollutant",does it mean that "amount" can be emitted??but i think it is pollutant (not amount) can be emitted?what's ur idea? many thx~~~

[RonPurewal]

How else would you write it?

I drank soda.
I drank 3 liters of soda.

Rain fell on Tuesday.
Several inches of rain fell on Tuesday.

I see what you're saying, but the only feasible way to write these sentences is to use "N units of xxxxx" in the same way as "xxxx" itself.

[momo32]

"Twice that you have" doesn't work.

Consider the following examples, each of which could be the second half of a comparison:
...twice the amount that you have
...twice the quantity that you have
etc.

With "that" (= pronoun) in there, you'd need ...twice that that you have. That's absolutely unreadable, of course, so you'll never see it.

Dear Ron,

I still cannot understand why "Twice that you have" doesn't work.
You mean that this kind of structure is not true or because the other choices is not right, we just find a better one. Consequently,We choose the choice with that.
THX

[RonPurewal]

consider:

The price of a beef egg roll is twice that of a vegetable egg roll.
(correct)

The price of a beef egg roll is twice of a vegetable egg roll.
(not correct)

the second construction is nonsense unless it's "twice ____ of a vegetable egg roll", in which the blank is some quantity.

"twice that you have" won't work for the same reason; it would need to be constructed as "twice the ____ that you have".

if this still don't make sense, then just memorize that this is a non-construction.

[momo32]

Dear Ron，

I think i got it.

you mean that when we use that to be a pronoun, we should have some modifier on that.

THX

[RonPurewal]

that's pretty much the point, yeah.

[JiangboW506]

Thank you Ron！
I read all the posters and have learned a lot.
:)

[RonPurewal]

excellent.

[ShriramC110]

Hi Ron,

Can you please tell me the difference in usage of that in these two sentences, second one is also a gmat prep problem.
Can you please tell me why the usage of that is correct in First Sentence and why the usage of that is incorrect in Second sentence

Providing initial evidence that airports are a larger source of pollution than they were once believed to be, environmentalists in Chicago report that the total amount of pollutant emitted by annually by vehicles at the O'hare International airport is twice that emitted annually compared to motor vehicles in the Chicago Metro area.

Since 1990 the growth of the global economy has been more than that during 10,000 years, from when agriculture began to 1950.

Thanks,

[RonPurewal]

post17023.html#p17023

read that whole post, but note in particular:

note that you can only use 'that' where the use of 'it' is incorrect.
if 'it' works, then you CANNOT use 'that'.

[aflaamM589]

Hello Ron,
Can B be crossed out because of incorrect idiom?

B) as much annually as is emitted by the

Thanks in anticipation

[RonPurewal]

there's no "idiom" problem... but, look at how the comparisons are structured in those two choices.

the correct answer is structured like this:

the total amount of pollutant emitted annually by vehicles at the O'hare International airport is twice that emitted annually by xxxxx

this actually makes sense.
each part is "the amount emitted annually by xxyyzz", and those two (similarly structured) parts are linked together by the "twice..." comparison.

__

choice B, on the other hand, is structured like this:

the total amount of pollutant emitted annually ... is twice as much annually as is emitted by xxxxx

this makes no sense.
since "annually" is already in the pink part -- the comparison -- it already applies to both parts.
so, the additional use of "annually" in the first blue part is redundant.
also, the two blue parts aren't parallel -- one is expressed as an annual rate, and the other isn't.