I think a countable noun are usually of the following 3 forms:

  • the + countable noun (single form)
  • a + countable noun (single form)
  • countable noun (plural form)

I am confused about which to pick for the following sentence. Should it be

The map is usually a crucial prerequisite for location services.


A map is usually a crucial prerequisite for location services.


Maps are usually a crucial prerequisite for location services.

2 Answers 2


The definite article, the indefinite article and the zero article can all be used when a noun phrase makes generic reference, that is, when it refers to a whole class, rather than just one or more instances of the class. In some contexts, just one of the three is appropriate, but all three sentences in your example can, to adapt the words of the ‘Longman Student Grammar of Spoken and Written English’, be understood to express a general truth about the class of things called maps.

In the second part of each sentence, you need to change ‘for location services’ to ‘for the location of services’ or ‘for locating services’.

  • 1
    They refer to different kinds of generic noun phrase, which are only one kind of generic construction. Nov 16, 2013 at 16:11
  • "...or ‘for locating services’." I think he meant "the services of locating things", which is a bit stilted. PS: Thanks for the reference to Longman - that one is new to me.
    – ZZMike
    Nov 16, 2013 at 23:59
  • It’s the stripped-down version of the magisterial ‘Longman Grammar of Spoken and Written English’ tinyurl.com/opdjk5q. One of its great merits is that it is corpus-based. Nov 17, 2013 at 7:00
  • 1
    While I agree with the fact that all three are grammatical, your second and third examples I think are going to be much more common while the first, definite example sounds a little stilted or stuffy.
    – DallaLiyly
    Nov 17, 2013 at 9:03

"The map " means "this one here". "A map" means any old map.

"Maps are usually a crucial prerequisite for location services" is a better way to put it (though grammatically, you have a plural subject, then a singular object, and a plural ending).

I would write "Maps are usually crucial for locating places" or even "Maps are essential for finding places".

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