1.I wash a car.(Active)
2.A car is washed by me.
In sentence #2,"a car" is the subject and "me" is the object.Is it right?My teacher taught me passive sentence.But It didn't match the passive structure.
Your sentences 1 and 2 are correct.
One thing, though -- to call "me" the object is not quite correct. Passive sentences do not have direct objects, but in your sentence "me" is the object of the preposition "by." There is a big difference.
Here is a good webpage with links to help you with active and passive verbs:
http://www.englishclub.com/grammar/verbs-voice.htm
Once you are clear on the information here, be sure to click on the link that says Now we'll look at the passive voice in more detail »