We have discussed about conditional clauses and conditional conjunctions already several times, see chapter 13. We have discussed this issue so often because the conditional part of a conditional clause can be constructed in many different ways, with a subordinate clause, see chapter 13, a gerund, see chapter 18.1.4, or an infinitive, see chapter 18.1.5. Depending on how it is constructed, we can use different conjunctions or no conjunction at all. We have discussed it as well in relationship to the futuro do conjuntivo, because if we use the conjunction se we have to use the futuro do conjuntivo, see 12.1.5. Furthermore we have to distinguish between a situation where the event / action has to be accomplished and a situation, where it does not have been accomplished. Of all the subordinate clauses the conditional clauses are the most complex ones.