Determiners include demonstratives which are this, that, these, and those. As determiners, this and that come before singular nouns, and these and those being plurals of this and that respectively are used in front of plural nouns.
Demonstratives this and that are used with singular nouns, while these and those are used with plural nouns.
Demonstratives this and these are used to indicate specific person/people, thing/things, etc. that is/are close to the speaker, and that and those show that it/they is/are not near to the speaker.
Nouns need not follow these determiners if the meaning is understood.
The determiners can also come before a number when the noun is understood.
If there is an adjective modifying a noun, the demonstrative comes before the adjective.
The words – this, that, these, those – besides being determiners, are also used as pronouns. One good way to distinguish between them is that a determiner, unlike a pronoun, comes before a noun.
|This potato is still hot.||This is a hot potato.|
|That duckling is ugly.||That is a very ugly duckling.|
|These apples are rotten.||These are rotten apples.|
|Those dark clouds are gathering overhead.||Those are dark clouds gathering overhead.|