2. RULE # 1 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.
3. RULE # 2 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.
4. RULE # 3 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.
5. RULE # 4 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.
6. RULE # 5 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?
7. RULE # 6 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?
8. PRACTICE कार्य करना आवश्यक है ! दिन बहुत लम्बा था ! उठने का समय हो गया है ! क्या गरीबों की मदद करना हमारा कर्त्तव्य नहीं है ? वह ललित था जो घायल हुआ ! क्या दूसरे देशों पर आक्रमण करना उचित है ? आपके के लिए सुबह की सैर लाभकारी है ! अभी ग्यारह नहीं बजे थे ! यह दुःख की बात है !