We use the active form to say what the subject does.
- He drove the car yesterday.
- I clean my house once a week.
We use the passive form to say what happens to the subject.
- The car was driven by somebody else yesterday.
- The house was cleaned only yesterday
Sometimes when we use the passive we do not know who did the action.
- My watch was made in Switzerland.
- My car has been damaged.
Sometimes we know who did something but it is not as important as what was done.
- It was sent by Harry yesterday.
- I was told by Sarah.
Often we use the passive to bring the topic we are interested in to the front of the sentence.
- The vegetables are all grown by local farmers.
- This door should be replaced when you have time.
Notice that the correct form is ' I was born' (not 'I am born'.
- I was born in 1987
- You were born in the same year as me.
Notice that the passive of 'doing' is 'being done'.
- I don't like you staring at me.
- I don't like being stared at.
- I hate people talking to me in clubs.
- I hate being talked to in clubs.
When things happen or change, and especially in informal English, you can use 'get' instead of 'be' in the passive.
- There was an accident but nobody was hurt
- There was an accident but nobody got hurt
- I was offered the job but I didn't take it.
- I got offered the job but I didn't take it.
You will find different grammar exercises and more grammar explanations on our sister site English Grammar Secrets