Modal auxiliaries Vs Primary auxiliaries Primary auxiliaries are be, do, have. They are used to form tenses and to frame short answers. Modal auxiliaries are will, would, may, might, shall, should, can, could, must, dare, need, used, ought. They are used to express moods.
Demonstrative Pronouns, which point out things, as this, these, that and those. Because they convey a high degree of specificity and distinctiveness in pointing out ("demonstrating") a referent; They are showing words.
They can be either a subject or an object in a sentence. We know which one to use by looking at the number of and distance of the thing(s) we are referring to. Use this and these when you are talking about things near you. Use that and those when you are talking about things farther away.
In writing, the demonstrative pronouns may take antecedents, but there is no fixed rule. The pronoun may point forward.
This is my answer
That was too much for me
These are good mangoes
Hand me those candles, please
We should not be confused with Demonstrative pronouns and Demonstrative adjectives.