The Second Conditional

     Unreal conditional sentences express imaginary situations. 

Structure

If + simple past, would + verb base form.

Example

If I had a plane, I would travel around the world.
If Andrea was a millionare, she would buy a big house.

Tips

1. If clause contains verb to be, use were for all the subjects.
Example: If I were an animal, I´d be a panda.
2.Unreal conditional can also be formed with the past continuous in the if clause.
Example: If I were leaving now, I might walk to work.
3. In the if clause, the simple past or past continuous does not indicate past time; it indicates that the situation is unreal. In the results clause, would, could-would be able to, or might also indicate that the results is unreal.
4.Would in the results clauses expresses more certainty than could or might about the imaginary results.

Video

Exercises

http://www.perfect-english-grammar.com/second-conditional-exercise-1.html

https://www.ego4u.com/en/cram-up/grammar/conditional-sentences/type-2/exercises?02