First and Second Conditionals

If you__________ free tonight, we can go out for a drink, or to the cinema.

He _________depressed if he fails the exam.

If I didn't know you, I _______ you were crazy.

If you had a bigger salary, you ______ more unnecessary things.

If it______for Tom, I wouldn't be here.

If they had this player, they __________a single match.

Our lives would be much easier if you ______ closer to home.

If people ... down trees, wild animals and plants ... .

Which sentence is correct?

If we ... around on foot, by bike or by boat, there ... so much air pollution.

If you ... the light when you are not in the room, you ... save energy.

If we ... nature, more species ...