Dear Jhua, you have chosen a hard topic to explain, even by us italian :-) You have to knew that the italian language is very difficult because we have a complicated grammar and often even any italians don't speak perfectly italian. Anyway, I'll try to explain: you use SIA and SIANO to say at subjiunctive but SIA is for the 1st, 2nd and 3th singular person and SIANO only for 3th plural person. Example: CHE io/tu/egli SIA bravo lo dice anche il maestro CHE essi (o loro) SIANO bravi lo dice anche il maestro. That is a particular kind to say but I recommend you don't use those because we, often, use to say at present simple insted at subjiunctive. Example: CHE io SONO bravo.... Che tu SEI bravo CHE egli E' bravo CHE esse SONO bravi Other kind to use SIA is like conjiunctin. Example: Ho visto SIA Mario CHE Luca (I have seen both Mario and Luca) Ho visto SIA Mario SIA Luca ( I have seen both Mario and Luca). Ok, I hope that my explanation has been useful. I'd like to know if you undestand what I wrote. In negative case, tell me. Bye :-)