I____ (discuss) the plan if he ____(come) to the meeting. - - 1º
I´ll discuss the plan if he comes to the meeting.
If I ____(have) 1 billion dolars, I ____ (buy) a new house. - - 2º
If I had 1 billion dolars, I would buy a new house.
If you ____ (use) air conditioning wisely, you ____(save) up energy. - zero
If you use air conditioning wisely, you save up energy.