Why don't you sit down? Now, there are several questions I must ask you if you don't mind.
Not at all. Go ahead.
What is the purpose of your visit to the United States?
I am going to attend a conference on air pollution. It will be held in the first two weeks of February at the University of California.
The University of California?
Yes, here is the official letter of invitation.
I see. Fine. When do you want to go?
I'd like to leave in mid-January if my passport is ready by then.