“It” is used to describe an object that both parties already know what you are talking about. This and That are used to show what you are talking about.
In English grammar, “it” can be used as a subject and object pronoun.
“This” and “That” are demonstrative pronouns and can also be used as adjectives.
Let’s learn more about what that means.
How to use “It”
We use “It” to refer to objects that both people understand through context of a previous conversation.
We do not use “it” for people.
Where is my guitar? I can’t find it.
What can I do with this T-shirt. Put it in the bin.
In the first sentence, “it” is the guitar and in the second sentence “it” is the T-shirt. We use the pronoun “it” to replace the noun(guitar) so we don’t have to keep repeating guitar.
“It” can also be the subject of the sentence:
It is a beautiful day.
It is wrong.
The noun is often implied and never explained because it is obvious from the context. In the first example, “it” replaces “the weather” and in the second example “it” could replace the exam question but we need more context to understand. This context is necessary to use “it”.
How to use This and That
This and that are used to introduce a new object/person into the conversation.
This is my wife.
We use This and That to add more context when the listener doesn’t know what object you are talking about.
What is this on the floor? Is it a guitar?
“This” can often be accompanied by some body language to help the listener understand such as pointing.
“This” is used for things that are near the speaker and “that” is used for things that are far from the speaker. (We use these and those for plural objects)
It,This and That in conversation
What is this pen doing on my desk?
It is a gift from your daughter.
This Saturday is not an option.
Is it your son’s birthday?
Yes, It is.
What is that over there?
It is a bird, I think.
It, This and That Difference
This and That are used to introduce an object and it is used to refer to that object when everybody understands what the object is.
This and That can be used with people but you can’t use it for people.