If Clauses

Question 1

To express what happens or will happen if certain conditions are met.

Answer 1

Use the preterit or future indicative in the main clause and the present indicative in the if-clause
(If we continue to cut down trees, the forest will disappear.)

Question 2

IF

Answer 2

Si

Question 3

To express a condition that is unlikely or contrary to fact

Answer 3

Use the imperfect subjunctive in the if-clause and use the conditional in the main clause. (If they invested more money in the airport, air traffic could improve.)