This tense, now used much less than in the past, is utilised in the following cases:1) To exhort someone to do something, instead of using the "imperativo"("Faccia pure come vuole!", ,equivalent to "do what you want".2) after words such as "che" and "bench ("Benché fossi 18 enne anni fa, …" 3) To express a doubt ("Che fosse calvo?": meaning "is he bald?").There are many other types of uses which distinguish it from the verb mode "indicativo" and it is really important to understand when congiuntivo is used and then choose to use it if in the right speaking situation.