It is a rule in the use of the articles that when a noun is used in the second time it is preceded by the definite article the. As it is a book. The book is in English.

I want to know whether this rule is true even when a noun is used in general. As in -

  1. Books are good friends of man.
    Books provide us with knowledge. (OR)
    The books provide us with knowledge. (in case of countable nouns).

  2. Iron is a useful metal.
    Iron is very precious for human life. (OR)
    The iron is very precious for human life. (in case of uncountable nouns).

Which sentences of them are right and why. Please clarify this point.

  • The a/the thing is for a context about the same thing: I saw a good movie last night. The movie was about the French Revolution. You have asked an interesting question. I have tried to answer the question, and I hope this helps you. Please note: this is a specific thing. It does not cover every usage of a/s plural morpheme and the.
    – Lambie
    May 20, 2018 at 18:23
  • You examples are stand-alone sentences so what I explain in my previous paragraph does not apply. However, Iron is very precious to human life would be followed by: The iron in these rocks, however, is not worth extracting. iron [general] becomes specific iron as of the second reference to it in the same context, paragraph, text or even speech. The way I have written those two sentences, means iron (general) become the iron (specific). The same is true for countable nouns.
    – Lambie
    May 20, 2018 at 18:56
  • I went into a house. It wasn't a house I liked. This is perfectly understandable. There is no necessity to use the in the second sentence. In fact, it would sound terrible if you did. So, your claim that it's a rule is false—unless you want to qualify it in some way. May 20, 2018 at 21:52
  • Even saying that you cannot use the with the first mention of a noun is wrong. The piece of toast I burnt tastes awful. May 20, 2018 at 21:56
  • @JasonBassford. Why can't anyone understand what I am actually saying? Where did I say you can't use "the" with a first mention??? I said that IF you have the article a to mean a random something, that random something then becomes the thing at the second mention. Why is that so hard to understand? It does not mean that the definite article the cannot be used in other contexts! I went into a house. It wasn't a house I liked. But the house was actually rather large. In many written contexts, a random something becomes defined. It's a typical pattern.
    – Lambie
    May 23, 2018 at 15:03

3 Answers 3


The sentence "The iron is very precious for human life" conjures up the image of a household implement used to smooth cloth or clothes by means of heat and pressure. Such implements are useful, but not normally thought of as precious. Leaving off the "The" (as the other "iron" sentence does) makes sense. Now the sentence "The iron in our food is precious for human life" makes more sense; but then, we have to ask, is "precious" the word we want? "Important" or "essential" for human life would be more accurate: iron is found in hemoglobin in our blood.

  • Well, not sure that "the iron" is very precious for human life. More like a useful tool.
    – Lambie
    May 20, 2018 at 21:42

The rule about using the the second time something is mentioned is not very precise. It would be better to think of the ___ as meaning "the SPECIFIC _____" - so you would not use it when referring to things in general.

For example,

Books provide us with knowledge

means books in general, but

The books provide us with knowledge

means some specific books that we have probably already mentioned.

It's the same thing with noncount nouns; iron means "iron in general", but the iron means "some specific iron".

Reference: Using Articles

  • The OP asked a question. The question has been asked several times. Also, I have been explaining a followed by the, not about every single use of a and the. This is one specific usage. There are others and also other rules. Your examples have nothing to do with the a/the thing in a context. Your examples are individual uses of plural nouns for general statements versus using "the". And please stop repeating what I have used as a kind of shorthand to explain the use of a something followed by the something in specific contexts where a term is repeated.
    – Lambie
    May 20, 2018 at 18:30
  • Please stop repeating it incorrectly: it is only for a context where a [noun, first instance] is followed by further clarification of that noun [second instance of the same noun in the same text] with the used in the same context. This also applies, basically, to speech. Someone is doing a disservice to these questions. For the record, I am not covering every single usage.
    – Lambie
    May 20, 2018 at 18:32

Iron is a useful metal. Iron is very precious for human life. (OR) The iron is very precious for human life. (in case of uncountable nouns).

Sample texts [which are not single sentences but together in a context]:

Iron is a useful metal. It is essential to many industrial processes. But the iron in these rocks is not worth extracting. It would be too costly.

Taking iron [pills] can lead to problems. The iron I take is prescribed by my doctor.

When you move from an uncountable or countable noun in the same context in a text or in speaking, you move from a general random thing to a specific thing. This move calls for using the definite article the second time you mention the thing. Below are some examples.

  • Coffee is a great drink. The coffee I drank yesterday at work was truly awful.

  • A girl was surfing all afternoon in front of our house. The girl wore a full wetsuit as the water was still nippy. The wetsuit was full of stripes.

  • Apples are a super fruit. But the apples on our tree this year didn't do very well. Probably because the weather was chillier than usual.

Please note: I have not covered every possible usage. But this contextual usage is hard for some ELLers especially for some, like Russian speakers, as there are no articles in Russian.

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