“This” and “These” are both English words used in a sentence. This is used for a singular countable noun and non- countable nouns, while these is used to describe plural countable noun.
A noun is a naming word and a countable noun are for things that can be counted. Example of countable nouns are a few mangoes, a house, a car and many more. Example of countable noun in a sentence: “This bread is soft”. “These books are not mine”.
An example of non-countable noun. This money belongs to my father’s friend. “This and “these” can also be used in another form when an object is near we use this or these and when it’s far we use “that or those”.
For example, “This book is interesting or these books are interesting”. For a distance object, “that book is interesting or those books are interesting”.