Whereas heat transferred between the ocean and the atmo

[RonPurewal]

you're welcome.

[TaoL266]

Between C and D, i'm a little bit concerned about the use of "is slow... and more rapid..." & "occurs slowly... and more rapidly", I have 2 questions as below:

1) How to distinguish the form of a modifier?(such as slow, which is both adj and adv, why we use slowly instead of slow when we need a adv modifier? Is it because of parallel since we have "rapidly" behind? )
these are the examples from the Manhattan SC guide book:
1. He runs quickly. He runs more quickly than Linda. (quickly as adv modifier)
2. He is quicker than Linda. (quicker as adj modifier)
3. He runs fast. He runs faster than Linda. (fast and faster as adv modifier)
why we don't use " He runs quick" since quick is also both adj and adv modifier? (This may be a simple question. But as a non-native speaker, I'm so
confused of this usage.）

2) the "more" used in the "is slow... and more rapid..." is another example that more does not need to come combined with than. So what is the intention or idiom here? Is the "more" express a kind of comparison or adversative?

Thanks a lot.

BR
Tony

[Sage Pearce-Higgins]

1) How to distinguish the form of a modifier?(such as slow, which is both adj and adv, why we use slowly instead of slow when we need a adv modifier? Is it because of parallel since we have "rapidly" behind? )

First of all, be careful that you're learning grammar terms with a view to helping yourself in the GMAT. English grammar (like any language's) is really pretty complicated, so you could easily spend years studying grammar but get no better at the GMAT.
Just to make sure, be clear about the difference between an adjective (which gives information about a noun), and an adverb (which gives information about a verb). Usually we form adverbs out of adjectives by adding 'ly' on the end. For example 'a beautiful dancer' or 'a person who dances beautifully'. One exception is the word 'fast', which can be both an adjective and an adverb.

why we don't use " He runs quick" since quick is also both adj and adv modifier? (This may be a simple question. But as a non-native speaker, I'm so
confused of this usage.）

No, 'quick' is an adjective, and 'quickly' is the corresponding adverb.

2) the "more" used in the "is slow... and more rapid..." is another example that more does not need to come combined with than. So what is the intention or idiom here? Is the "more" express a kind of comparison or adversative?

In most cases a phrase with 'more' needs to be followed with 'than'. If I said 'You have more money.' I need to know 'than who?' or 'than when?' to make sense of your sentence. However, if the meaning is clear, then we don't need to use 'more'. For example, the sentence 'I have $20 and you have more.' has a clear meaning. We don't need to say 'I have $20 and you have more than $20.' Leaving out extra words and phrases when the meaning is clear is called ellipsis and is very common in English.
As an exercise, take the correct answer C and try to add in the words that have been left out. Finally, I encourage you to think more about the meaning of the sentences that you find on GMAT.

[TaoL266]

1) How to distinguish the form of a modifier?(such as slow, which is both adj and adv, why we use slowly instead of slow when we need a adv modifier? Is it because of parallel since we have "rapidly" behind? )
First of all, be careful that you're learning grammar terms with a view to helping yourself in the GMAT. English grammar (like any language's) is really pretty complicated, so you could easily spend years studying grammar but get no better at the GMAT.
Just to make sure, be clear about the difference between an adjective (which gives information about a noun), and an adverb (which gives information about a verb). Usually we form adverbs out of adjectives by adding 'ly' on the end. For example 'a beautiful dancer' or 'a person who dances beautifully'. One exception is the word 'fast', which can be both an adjective and an adverb.

I can distinguish the function of adjective and adverb modifiers, the only concern is that how to use a word when it works fine both as adverb and adjective.
You're right that the most effective way to deal with the GMAT exam is not go too deep into this kind of grammar issue, which, sometimes, is too hard for a non-native speaker to fully understand.

why we don't use " He runs quick" since quick is also both adj and adv modifier? (This may be a simple question. But as a non-native speaker, I'm so
confused of this usage.）
No, 'quick' is an adjective, and 'quickly' is the corresponding adverb.

From the Oxford Dictionary, quick is also an adverb. examples are as follow:
" Come as quick as you can"
"It's another of his schemes to get rich quick. "
Maybe I should not go too deep on this issue too!

2) the "more" used in the "is slow... and more rapid..." is another example that more does not need to come combined with than. So what is the intention or idiom here? Is the "more" express a kind of comparison or adversative?
In most cases a phrase with 'more' needs to be followed with 'than'. If I said 'You have more money.' I need to know 'than who?' or 'than when?' to make sense of your sentence. However, if the meaning is clear, then we don't need to use 'more'. For example, the sentence 'I have $20 and you have more.' has a clear meaning. We don't need to say 'I have $20 and you have more than $20.' Leaving out extra words and phrases when the meaning is clear is called ellipsis and is very common in English.
As an exercise, take the correct answer C and try to add in the words that have been left out. Finally, I encourage you to think more about the meaning of the sentences that you find on GMAT.

The full more... than... structure in choice C might be like this:
The transfer of heat between the ocean and the atmosphere is slow when the ocean is colder than the air and more rapid when the ocean is warmer than the air than when the ocean is colder than the air.
This sentence is too awkward.
I think I get your idea. when we omit some words in a sentence, it does not only make the sentence more concise but also express our meaning more effectively, and this might be the reason that ellipsis is so common in English (also in any other language). ^_^

BR
Tony

[Sage Pearce-Higgins]

From the Oxford Dictionary, quick is also an adverb. examples are as follow:
" Come as quick as you can"
"It's another of his schemes to get rich quick. "
Maybe I should not go too deep on this issue too!

Be careful here: regular spoken English and GMAT English are quite different. This is a good example of GMAT favoring slightly formal, old-fashioned usage and an objective style. Both of those examples are of the kind of English spoken in an informal way and use 'quick' as an adverb much like 'fast' can be used as an adverb.

The full more... than... structure in choice C might be like this:
The transfer of heat between the ocean and the atmosphere is slow when the ocean is colder than the air and more rapid when the ocean is warmer than the air than when the ocean is colder than the air.

Great, you got it!