This document discusses conditional sentences using different verb tenses in the if-clause and principal clause. It provides two examples: the first uses a present simple verb in the if-clause and a future verb in the principal clause, while the second uses present simple verbs in both clauses. These examples demonstrate how conditional sentences can be formed with different verb combinations in the if-clause and principal clause.

2. If clause Principal clause
Present simple Future (will)
If you read this book, You will like it
Present simple Present simple
If you put water in the cooler, It freezes (hechos cientificos)

3. If clause Principal clause
Present simple Future (will)
Present simple Present simple