The forms is, am and are are used in the present tense; was and were are used in the past tense.
Was and were are used in the past tense.
Use was when the subject is a singular noun or a singular pronoun like I, he, she or it.
- I was waiting for his call.
- He was busy with his work.
- She was angry with her husband.
- It was raining.
- The boy was solving the sum.
- The girl was dancing.
- The bird was singing.
Use were when the subject is a plural noun or a plural pronoun like you, we and they.
- You were sleeping then.
- They were having a lot of fun.
- We were waiting for them.
- The birds were singing.
- The boys were playing.
- The girls were dancing.