Usi speciali del futuro
1. In Italian, the future tense is often used to express what is probably true or to speculate or guess about what could be true. This usage is called the future of probability (il futuro di probabilità). In English, probability is expressed with words such as probably, can, could, must, or I wonder. In Italian the future tense alone is used.
-- Non vedo Amelia da molto tempo. Dove sarà?
-- I haven't seen Amelia for a long time. Where could she be?
-- Forse sarà in vacanza.
-- Perhaps she is on vacation.
-- I signori vorranno una camera con bagno, vero?
-- The gentlemen probably want a room with a bath, right?
-- Che ore saranno?
-- I wonder what time it is?
-- Saranno le undici.
-- It's probably eleven o'clock.
2. When the verb of the main clause is in the future tense, the future is also generally used in dependent clauses beginning with quando, appena, and se. English, in contrast, as you will see in the following sentences, uses the present tense in the dependent clause.
Quando arriverà, sarà stanco.
When he gets here, he'll be tired.
Scriveranno appena potranno.
They'll write as soon as they can.
Se farà caldo, staremo all'ombra.
If it's hot, we'll stay in the shade.