What is the difference between futurum exactum and futurum simplex? I have to learn both for an upcoming test, but I don't know the difference between the two. I do know the lines, but what is the difference between the two and how are they used?
Futurum Simplex (simple future, future imperfect)
The simple future, amābō, is the most common future tense. It refers to something which is going to happen in the future: "I will love". In general, "will" is the best way to translate this into English.
You form the simple future in two different ways:
- In the first (amāre) and second (habēre) conjugations, you take the present stem (amā-, habē-), and add the endings -bō, -bis, -bit, -bimus, -bitis, -bunt.
- In the third (currere, capere) and fourth (audīre) conjugations, you take the present stem (curr-, capi-, audi-), and add the endings -am, -ēs, -et, -ēmus, -ētis, -ent.
Futurum Exactum (futurum perfectum, future perfect)
The future perfect, amāverō, is much less common, and doesn't have a direct analogue in English. (EDIT: Or perhaps it does. See the comments.) It's used for something which happens in the future, but before something else.
English tends to use present-tense forms for this: "After I get home, I will eat dinner." In this sentence, "get home" is referring to a future event, happening before another future event (eating dinner). So in Latin it would be translated with a future perfect (domum redīverō).
If you really need to make it clear in your translation, you can use "will have", but this tends to sound awkward in English: "After I will have gotten home, I will eat dinner." I'd never say something like that except in a translation exercise.
Fortunately, it's easy to form, without any weird exceptions that I'm aware of. Take the perfect stem (amāv-, habu-, cucurr-, cēp-, audīv-), then add endings based on the future tense of esse (erō, eris, erit, erimus, eritis, erint).
The third person plural is the one to watch out for: since -erunt is already the ending for the perfect tense, the future perfect is -erint. All the rest are exactly like the forms of esse.
From what I understand in the comments, where you say 'amabo' is futurum simplex and 'amavero' is futurum exactum, what you are actually asking about is the difference between what most Latin scholars would call the future tense and the future perfect tense. The future tense (amabo, your 'futurum simplex) is simple a verb tense referring to an action that will occur - for example, amabo means 'I will love'. The future perfect tense (your 'futurum exactum') refers to an action that will have occured - i.e. amavero means "I will have loved". All you really need to know to translate them correctly is "will vs. will have". When you see the normal future verb endings (-o,-s,-t,-mus,-tis,-nt, in the first conjugation), translate as "will". When you see the future perfect endings, using the third principle verb part (-ero,-eris,-erit,-erimus,-eritis,-erint), translate as "will have". I hope this is the answer you were looking for.