The question title says it all. I'm working on the sentence

The temperature of the hot and cold reservoirs limit the maximum possible efficiency.

And I think the verb should be "limit" because the subject is the temperature of the reservoirs. However, Word is suggesting "limits", maybe it is assuming the subject is temperature?

I just wanted to make sure I was thinking about this correctly.

Thank you!

  • 2
    Temperature limits; temperatures limit. Commented Oct 18, 2017 at 15:31
  • Though temperature may be used in non-count usage, this is not a good choice here. You're looking at two different components, not a gestalt. 'Bacon and eggs are [both] found on aisle 14.' Commented Oct 18, 2017 at 18:23

2 Answers 2


There are many reservoirs, each with its own temperature.

In this case, the subject is "the temperatures of the hot and cold reservoirs"

What do the temperatures do? They limit.

"The temperatures of the hot and cold reservoirs limit the maximum possible efficiency."

  • 2
    To nitpick on a completely irrelevant point, "each with its own temparture." Reservoirs aren't people, so you shouldn't use singular they. Commented Oct 18, 2017 at 15:33
  • A good way to parse these phrases is to remove the prepositional and other clauses and simply the structure. The grammar will carry forward to the complex version also: The temperature...*limits* the efficiency. Commented Oct 18, 2017 at 17:49
  • Unless you're going to analyse the 'unitary' notion ('bacon and eggs is my favourite breakfast') as opposed to the 'separate components ' notion ('bacon and eggs are [both] getting a lot more expensive') (which has been done many times before), this becomes a simple issue of number agreement. That is not a topic for a site devoted to linguists.... Commented Oct 18, 2017 at 18:28
  • No, don't use plural temps, use singular temp. The singular distributes. This is idiomatic for the past 400 years in science and engineering. I don't much care which verb is used, but I do care about the singular temp. Google "temperature(s) of the hot and cold". The first are all native English speaking authors. The latter begins with your answer, and is followed many very nonnative looking names I haven't read. Ngrams returns very authoritative works for the former, not so much for the latter.
    – Phil Sweet
    Commented Oct 18, 2017 at 22:55
  • @Phil: but in this case, it's a function of the two temperatures taken together that limits the efficiency, not either temperature alone. So I think you need to use temperatures. Commented Oct 19, 2017 at 1:19

Try substituting "temperature" with "size" or "cost" in the sentence. Would you use the plural or the singular?

As @EdwinAshworth alludes to in the comments, it could be either "temperatures ... limit" or "temperature ... limits" depending on whether the intent is for the reservoirs' temperatures to be regarded collectively ("temperature") or individually ("temperatures").

Consider, by way of analogy, the following:

The choice of the voters is what will ultimately decide the matter.

The choices of the voters are what will ultimately decide the matter.

"Choice" could be singular or plural depending on which perspective the speaker/writer wishes to emphasize.

(Related discussion at Temperature vs Temperatures )

Examples using temperature in the singular:

  • Measure the temperature of both the turkey and stuffing! (Associated Press article, 2011)

  • In the females, an analogous vascular net helps regulate the temperature of developing fetuses. (article in Natural History, 2003)

  • The refrigerator is well featured in several other respects: Two thermostats control the temperature of the fresh-food and freezer compartments.... (article in Popular Mechanics, 2001)

  • Model ST250 has been designed to be accurate to +2 percent of full scale when measuring the temperature of boilers, air ducts, motors, bearings, or furnaces up to 120 degrees C. (article in Mechanical Engineering, 1997)

  • By measuring the speeds of different waves, astronomers can determine the temperature of different layers because the speed of sound increases as temperature increases. (article in Astronomy, 1995)

  • Automated control systems are now commonly used to control thermostat settings, the temperature of chilled water and hot water coils, and the amount of air-flow.... (article in Mechanical Engineering, 1994)

Examples using temperature in the plural:

  • To ensure that the liquids are being stored safely, the temperatures of the railcars must be checked at least once a day. (article in Mechanical Engineering, 2008)

  • Up to this point in the investigation, testing used heaters that simulated the temperatures of computer chips in operation. (article in Mechanical Engineering, 2001)

  • At a computer keyboard in a comfortable office, he was recording the temperatures of 15-ton steel ingots immersed in the soaking pits where they are reheated. (article in the New York Times, 1993)

  • The temperatures of individual areas of skin were converted into a useful depiction of temperature patterns by jotting each temperature on a gridded diagram of the lower limbs.... (article in Journal of Rehabilitation Research & Development, 1996)

Without further context, I would lean toward using:

The temperature of the hot and cold reservoirs limits the maximum possible efficiency.

under the assumption that the unitary sense of temperature is being emphasized here, and thus temperature is uncountable.

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