About Record of U.S. Entry and Departure Form

Hi everyone,

I am now filling out this form, but have some questions.
Q1: "I was a student in the U.S. on an F-1 Visa for ___ years prior to the year 2019."
Since I came to U.S. in Aug. 2016, I am not sure whether I should fill 2 or 3 (years) in the blank.
Q2: In the form, it requires my U.S. address. Since my current home address will not work after this month, so can I fill in my (university) office address instead?
Q3: For the last table (entry & departure record), I only went back to my country once (in last summer) from 08/2016 (arrived at U.S. for the first time) to now, what should I fill in the blank for year 2017, 2019? Or just leave them blank? Since I was always in U.S. in year 2017, 2019.

Your any help and suggestions are greatly appreciated!