Remember: Conditional forms are used to wonder about something that can happen, or to express that some action can only take place if something else is done first.
We use the 2nd Conditional to talk about an event that is not likely to happen. The form of the 2nd Conditional is: If + past tense verb, + would + verb.
- event that is not likely to happen → probable result
- If I won the lottery, I would travel around the world.
The 3rd conditional is used to imagine the possible results of an event that did not actually happen. The form of the 3rd Conditional is: If + past perfect +, (would have + past participle).
- event that did not happen → possible past result
- If I had studied hard, I would have gotten a good grade.
You can also put the 'if' clause at the end of the sentence. For example: "I would have gotten a good grade if I had studied hard." or "I would travel around the world if I won the lottery."