"Five thousand tons of water flow/flows"?



Every minute, five thousand tons of water flow/flows over a cliff into the river below.

Should the verb 'flow' be conjugated in singular or plural in this sentence?


Posted 2015-04-18T15:48:45.647

Reputation: 101

1You might be interested in the topic of *measure phrases*. – F.E. – 2015-04-18T22:02:49.813

2I am usually a stickler for number agreement between noun and verb, but since "tons" cannot flow, but water can, I would say "tons of water flows". I would also say "12 inches of rain in one hour is a lot of rain". – Tᴚoɯɐuo – 2015-04-19T11:24:08.197

@TRomano Interesting I would definitely say "12 inches of rain in one is a lot of rain" but I think at least part of the reason is that you repeat "is a lot of rain" Consider "12 inches of rain in one hour are a lot." I could still live with both is and are and might use is but are is much less awkward in this case imo. – DRF – 2015-07-24T11:52:50.890



Ordinarily, "flows" would be best, as the other answers have stated. There are, however, exceptions.

Recognizing that "water" is the subject, "flows" is then the natural verb, but there are constructions in which attention is focused on "tons". For instance, when describing a hydroelectric plant, you might find something like "Five thousand tons of water flow through the generators every minute, with each ton producing a kilowatt of power."


Posted 2015-04-18T15:48:45.647

Reputation: 4 265

The subject of the sentence is "tons"; countable units. Water is uncountable but here it only describes "tons"; doesn't serve as the subject itself. – SF. – 2015-08-05T12:10:11.137

water is countable as well! The waters of Indian Ocean and Pacific Ocean @SF. – Maulik V – 2015-08-05T12:23:34.533

Agreed. On first reading, "tons" is a modifier for "water", an (usually) uncountable noun, but it could also be said that "of water" is a modifier for "tons". – TBridges42 – 2015-08-05T16:35:19.873

1@MaulikV In that sense it's plural but not countable; you can't say *two waters or *three waters with that meaning. It is countable sometimes, though. At a restaurant, you can ask for two waters when you order your food. Still, none of this is relevant to the OP's question, in which water is not countable. – snailplane – 2015-08-05T17:53:40.393

@MaulikV: Water can be countable, but in standard usage (like in the question) it's uncountable. "Mineral waters" could mean "bottles of mineral water" or "springs with different mineral waters". The "waters of" means "different areas". But the tapwater is just singular. – SF. – 2015-08-06T08:05:21.403


Partitive Construction denotes a part of a whole.

For example -

a piece of cake [ => a piece (portion) from a large one]

Measure partitive nouns -

The measure partitives relate to precise quantities denoting length, area, volume, and weight, for example (note the compulsory of):


a foot of copper wire
a metre (BrE) / a meter (AmE) / a yard of cloth
a mile of cable


an acre / a hectare of land


a litre (BrE) /a liter (AmE) of wine
a pint / a quart of milk


an ounce of tobacco
a pound of butter
a kilo of apples
a ton of coal

Measure partitives can be either singular or plural:

a / one gallon of water
two / several gallons of water

If count, the second noun must be plural:

one kilo of apples
two kilos of apples [NOT apple]

Reference - A Comprehensive Grammar of English Language [Page No. 251 (5.8)]

The expression in question is an example of measure partitive:

Five thousand tons of water

The verb that follows this expression can be either a singular or a plural. It depends on the writer/style or what the writer emphasis on.

While the average human requires only about 4 liters of drinking water a day, as much as 5,000 liters of water is needed to produce a person's daily food requirements.

About a million tons of lava are pouring every day from the fissure which opened on the Sicilian volcano in December.

So in the following sentence both flow and flows are correct -

Every minute, five thousand tons of water flow(s) over a cliff into the river below.


Posted 2015-04-18T15:48:45.647

Reputation: 10 615


This is a matter of identifying the simple subject. The subject here is water, not tons. tons is not what is flowing here.

The simple subject is the subject without any extra descriptions or qualifiers. "thousands of tons" is just an extra description of water.

You'll know you have the simple subject because it can stand alone as the subject of a sentence. "Water flows over a cliff into the river below" is a complete and valid sentence.


Posted 2015-04-18T15:48:45.647

Reputation: 131


What a good question. After much research, my best revised answer:

First, what is the subject? The subject is "tons" because it can be counted (5000 tons); therefore, it does not qualify as a quantifier such as "lots of" (when "lots of" functions as an adjective). That brings us to our problem--"lots of clothing"--for example. Without proper context, it could be a quantifier + subject meaning many clothes, or it could be a plural noun + adjective prepositional phrase--"Ten lots of clothing are for sale."--but, in this case, the proper context was given--5000 tons--so, the plural verb "flow" would be correct. My English teacher would have argued that "tons" should not be used informally anyhow, but times change.


Posted 2015-04-18T15:48:45.647



It should be "flow". The basic rule is "Singular noun has a verb with an 's' and plural verb has verb without an 's'" So since there are five thousand tons of water, you want just "flow". Now if there's only one ton of water, say:

Every minute, one ton of water flows over a cliff into the river below.

Some nouns are not plural or singular. We call these mass nouns. If the subject is a mass noun, you would use verb with an 's'. For example

Every minute, water flows over a cliff into the river below.

Welcome to the site!


Posted 2015-04-18T15:48:45.647

Reputation: 4 697

My problem was to know whether the subject is 'tons' or 'water'. – user18982 – 2015-04-18T16:25:19.137

It's actually both. The subject is "five thousand Tons of water". – James – 2015-04-18T16:26:58.160

1so,we look at "tons" which is plural and we conjugate the verb accordingly,right?thank you – user18982 – 2015-04-18T16:56:23.057

1Exactly, you are correct. – James – 2015-04-18T16:57:54.810

3"Five thousand tons of water flow" is correct, but both "tons" and "flow" are plural. Look at "it flows" and "they flow". The first is singular, the second is plural. – aparente001 – 2015-04-18T19:43:29.503

1Huh? Your whole answer seems to be confusing. E.g. ==> The basic rule is "plural noun + singular verb, singular noun + plural verb." – F.E. – 2015-04-18T21:58:56.107

I'm sorry, I could have explained that a lot better. When I said "plural verb" I meant verb that ends with 's'. I'll edit my answer. – James – 2015-04-18T22:42:39.043

@DJMcMayhem, it looks like it could still do with some editing. "Singular noun has a verb without an 's' and plural verb has verb without an 's' " What? A singular noun is when there is ONE of something. "This cupcake tastes delicious." There is one cupcake. It doesn't have an S. It is singular. The verb is conjugated accordingly and has an S. No matter how you look at it (upside down or sideways), this is SINGULAR. Plural is the other kind. For example, "These cupcakes taste even better." – aparente001 – 2015-04-19T01:53:55.860

facepalm I know that. it's a typo. – James – 2015-04-19T01:55:31.610

Thanks for fixing it, @DJMcMayhem. ELLs already have it tough without us making things incredibly confusing for them. – aparente001 – 2015-04-19T02:36:52.693

The verb form with -s is the third person singular present form. It's the present tense form that agrees with a third person singular subject: he/she/it walks. The third person part is important; we say I walk, not *I walks. – snailplane – 2015-04-24T23:22:53.547