2. If they ask what guaranties if you are coming back to your country after your studies, i am Tunisian and i live in Saudi and i go to study in states if i will succeed in interview, my family are in Saudi working there?

you have to prove that you will come back after your study.To prove that you say that I will come back to my country bcoz there are so many top companies which give me opportunity to work on my field(whatever your field & major subject)and my family have strong economical background so i dont need to stay there for business purpose.My ambition and main purpose to go us is only for study.(get information about your field related company,you must have all information about your desired company like is growth,demand,salary package etc.)Ok
wish you all the best

3. I have applied for MS in IT in USA. My interview is on 13th July. I want to know wt will the answer of this question. What will u do in IT?

Information technology leads everything in today's world.
technology is in every where and in all the fields. i would
like to get specialized in the IT filed in order to improve
my knowledge and career prospects and to innovate new

4. My qualification is MCA and I am applied for MS in Us I got I-20 from University of Bridgeport? I am having doubt if visa officer asks me you are already masters, then what is the need to go for masters?

In india masters degree means not expertise in particular
subject. Where as in MS we can be a expert in all subject
bcoz we submit a project on each sunject where as in india
not like that. In future I wan do Ph.d in particular area.
So i need MS education to my carrer.