I am confused with the use of one of . For ex : Although

1. Although they are crucially important, a person's total calorie intake is only one of the many factors that determinee if their weight will increase or decrease.

In the above sentence, the subject is plural( factors) because not one , but all the factors determine if the weight will increase or decrease. Thus, in spite of the usage "one of" plural form of verb is used.

2. Since 1989, when the Berlin Wall was demolished, one of the most problematic ethnic groups in the reunified Germany, in terms of cultural and economic assimilation, has been the former East Germans, who have had to acclimate to an entirely different political system.

This sentence is referring to only one subject (ethnic group) out of many , so it has taken singular form 'has been'.

I hope it helped.

I understand it is very confusing to differentiate these two cases. However, if you concentrate on intended meaning of the sentence, it will help more often than not.

Although they are crucially important, a person's total calorie intake is only one of the many factors that determine if their weight will increase or decrease.

In this sentence, presence of 'that' makes 'many factors' (instead of 'only one of the many factors') subject of the sentence.


Since 1989, when the Berlin Wall was demolished, one of the most problematic ethnic groups (in the reunified Germany, in terms of cultural and economic assimilation), has been the former East Germans, who have had to acclimate to an entirely different political system.

In this sentence, absence of any conjunction word makes 'one of the most problematic ethnic groups' subject of the sentence.

I am afraid the choice you have cited for the first sentence is a flawed one. We cannot base a discussion on a wrong choice. What are the other choices or what is the correct choice? For example, what does their refer to? Why is if used rather than the customary whether. Can you please provide these info?

In the second case, the subject is one group of people namely the EGs, the word one representing a collective noun, which is considered singular. Therefore, the verb is singular. Please note that there is no restrictive pronoun that in the second case as you find in the first choice, the factors that determine ; the pronoun that stands for the plural factors and hence the verb takes the plural avatar.
This is as per obedience to the touch rule of the relative pronoun.

the correct choice is this
it is crucially important, a person's total calorie intake is only one of the many factors that determine whether his or her weight will increase or decrease

but here also the one of many factors is plural.
and i thought that pharse "one of" always takes a singular verb
such as "one of the ships has gone down"

Its confusing
can anybody explain?

Marcab, could you elaborate,
I am not sure if I understood completely




The army of ants are marching forward. - INCORRECT
The army of ants is marching forward. - CORRECT

Have I inferred correct?

See,
If you need to simplify this entire rule, then one thing you must note; here we have used prepositional phrase.
Honestly speaking, there is nothing to remember here. Just go with the basics of prepositional phrases.
prepositional-phrases-clarified-144981.html
After going through the above link, you would breeze away through the entire rule. There is nothing to remember it.
Let me know if anything remains unclear.

Its a simple rule:

One of the “noun” (always plural) + that/who + plural verb
One of the “noun” (always plural) + singular verb

Hi Marcab,
The general rule mentioned above totally makes sense...kudos..

Can you help to clarify some details in red above?

Cheers

Team,

After going through all posts above , can official GMAT Club Member or SME helps to summarize when one should use single and plural form of verb following "one of ...structure" ?

if you have just ONE OF THE + PLURAL NOUN + WHO/THAT + ______, and it's NOT "the only one", THEN "____" MUST be a PLURAL VERB.
zero exceptions.

example:
that's one of the birds that fly over my house at night.

here's the rationale, if you care about reasons: the idea is that there is a whole group of NOUNs (whatever they are) that do ______, and we're singling out one of them.

notice that the RED-COLORED RELATIVE PRONOUN (WHO/THAT) is absolutely crucial here.
if that isn't there - i.e., if "one of the NOUNs" is actually the SUBJECT of the ____ verb - then you take a singular verb instead.
example:
one of the birds flies over the house; the other one flies past it.

--

finally, to complicate things further, THE ONLY ONE OF THE + PLURAL NOUN + WHO/THAT + ______ requires a SINGULAR verb for the "_____".
in this case, only one of the NOUNs actually does whatever "_____" refers to, so we stick with the singular verb.

example:
Marina is the only one of the girls who has ever been to India.


the following examples are both correct:
(1) he is one of the people who bake special cakes.
(2) he is the only one of the people who bakes special cakes.

this actually isn't as hard as pure memorization might make it seem: all you have to do is think about the LITERAL MEANING of what you're writing.
in my #1, there are lots of people who bake special cakes, so "bake" should be plural.
in my #2, the man in question is the ONLY person who bakes special cakes, so the verb should be singular.

--

here's another way to think about it: you can DECONSTRUCT the sentence, and tell exactly which noun / construction the verb "belongs" to. (i have no idea whether this is a formal grammar concept or not, but it works.)

in my #1:
PEOPLE bake cakes. (--> plural "bake")
he is one of them.
(he is not "one who bakes cakes")

in my #2:
there are a bunch of PEOPLE.
he is THE ONE who BAKES cakes. (--> singular "bakes")
(there are not "people who bake cakes")

CAVEAT:
this is one of those things that are RIDICULOUSLY hard to memorize, but is actually pretty easy just to deduce from context. so, unless you're prepared to memorize a whole lot of easily confused, easily forgotten rules that are extremely subtle, you should just think about the context and go from there.

* for instance, given
X is only one of the factors, albeit an important one, that (keep/keeps) the market from spinning out of control
it's clear that there are MANY factors, ALL of which keep the market from doing blah blah blah, and that X is just one of them.
since there are MANY factors keeping...., we should use the plural "keep".

* on the other hand, given
X is the only one of the factors that (keep/keeps) the market from spinning out of control
it's clear that there are many factors, but NONE OF THEM EXCEPT X keeps the market from doing blah blah blah.
since X is the ONLY factor keeping...., we should use the singular "keeps".

In 99.9% of these, you'll be able to just think about the context in this way, saving yourself a horrendous amount of time and effort.

(The above answer has been taken from Ron's answer on BTG.)

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