The structure of a second conditional sentence
Like a first conditional, a second conditional sentence consists of two clauses, an "if" clause and a main clause:
If the "if" clause comes first, a comma is usually used. If the "if" clause comes second, there is no need for a comma:
We use different verb forms in each part of a second conditional:
*Note that this "simple past" form is slightly different from usual in the case of the verb BE. Whatever the subject, the verb form is "were", not "was": If I were rich, I'd buy a big house.
Using the second conditional
The second conditional is used to talk about things which are unreal (not true or not possible) in the present or the future -- things which don't or won't happen: