Articles for concrete uncountable or abstract nouns
Secondly, only the definite article can situate articles in front of uncountable or abstract nouns under some special circumstances. Basically, uncountable concrete nouns are defined as something tangible and can be felt by five senses. When these nouns refer to general things in the context, they should not follow "the". If an uncountable concrete noun refers to a specific thing, “the” can be used with it. From (2a), "money" is uncountable and non-specific. In contrast, "the money" is used in (2b). It denotes that "the money" is a definite referent known by the undergoer and mentioned by the doer before. More importantly, "you lost before" in (2b) is a non-restrictive appositive that complements "money". Therefore, "the" should be used with uncountable nouns.
Some plural uncountable nouns can be used with “the”. From examples (3a) and (3b), "glasses" and "jeans" are concrete, uncountable and plural. They have no singular form but only refer to a specific object and subject. Hence, only a definite article is appropriate in these cases.
Uncountable abstract nouns can also be placed before “the”. Abstract nouns cannot be physically experienced, but they are not unreal. In (4a), "weight" is a generic noun. However, in (4b), "the'' placed in front of "weight" refers to a specific time and the defining relative clause used after the noun "weight" indicates the exact time. Then, only when an abstract noun is specified, should the definite article be used before it.
As time-related nouns are considered abstract nouns in general. However, “the” can be positioned in front of some time-related nouns which indicate certain parts of the day, like "in the morning / afternoon / evening”. Yet, other time-related nouns do not contain articles after the prepositions, such as“at noon / night / midnight”. The important factors determining the use “in the” or “at” depend on the length of time and specificity. “Morning”, “afternoon” and “evening” occupy longer periods in a day; however, “noon” and “midnight” are particular time points in a day. Hence, using “at” can signal the preciseness of time. Even though “at night” is used commonly, “night” seems to be a period instead of a particular time. It is more generic while “in the night” refers to a specific night that something happens. However, “the” is not the key factor in determining whether “morning/ afternoon/ evening” are non-specific or specific. For example, “in the morning” refers to any morning in general. However, changing the preposition from "in" to "on" can make the phrase and the time specific. It is concluded that the definite article is not only used to refer to something specific.
Last but not least, the definite article can change the parts of speech from an adjective to a noun. For example, “the elderly” and “the poor” refer to specific groups of people who share some characteristics of the adjectives. Moreover, many nationality adjectives followed by “the”, like “the Spanish” turn into nouns to show people’s nationalities. Nevertheless, not all nationality adjectives can have this change. If the word ends in “-an”, there is no article before it and “-s” should be added instead.