Mark the alternative with the correct use of If-Clauses: He would have had lunch with you if you had let him know you were free. They would have go...

Mark the alternative with the correct use of If-Clauses:
He would have had lunch with you if you had let him know you were free.
They would have gone to the concert if they bought the tickets in advance.
If you heat the water at 100 degrees C, it will boils.
I would tell you that if you understand me.
I will fix the bike if you gave me the tools that I need.


a. He would have had lunch with you if you had let him know you were free.
b. They would have gone to the concert if they bought the tickets in advance.
c. If you heat the water at 100 degrees C, it will boils.
d. I would tell you that if you understand me.
e. I will fix the bike if you gave me the tools that I need.