We use "do" for emphasis. "We like hummus." "No, you don't." "Yes, we do like hummus!"
I find it best to use a dictionary to understand the subtle differences between words. "Strange" is something that is not previously known, something that is unusual, or uncommon. A person not previously know is a "stranger". "Weird" is something that is supernaturally mysterious or fantastically strange, eerie, unusual, or startlingly odd.
Most of us don't seem to know the difference between these words anymore and use them interchangeably. My small English/Arabic dictionary translates "strange" as "خريب" and weird as "خريب الاطوار". I hope this is helpful.