When there is no Real Subject in the
sentence then the Subject is introduced by
“IT”
Ex.
It is cloudy today.
It was very cold last night.
It was extremely hot last Sunday.
When the Subject is not certain then the
Subject is introduced by “IT”
Ex.
It was noise which was disturbing us.
It is horn which is honking.
It is tree which provides us wood.
In Present Tense we use “IT IS” and in Past
Tense we use “IT WAS”.
Ex.
It is water which quenches thirst.
It was machine which was making noise.
It is you who tease me.
It was Sita who stood first in the class.
In Negative Sentences, „NOT‟ is used with IT
IS / IT WAS
Ex.
It is not rain which spoils crops.
It was not sharing that causes aids.
It is not cat that barks.
It was not I who lied.
In Interrogative Sentences, we use is/was
before the use of “IT”.
Ex.
Is it good to tell a lie?
Was it bad to help someone in need?
Is it a crime to smoke in public area?
Was it profitable to start business?
In Interrogative Negative Sentences, we use
NOT after the use of “IT”.
Ex.
Is it not our duty to pay tax?
Was it not their fault?
Is it not good habit to speak truth?
Was it not bad to behave like that?