Maral33... Decades ago, maybe in the 1930s, 1940s, etc., in many regions, it was more common to call out to a gentleman to get his attention by saying, "Hey, mister!" I have seen that in old movie films.
Nowadays, "Mister" as a title before a known name is more commonly heard, like, "Here are the keys to your car, Mr. Smith." "SIR, do you need a taxi?" would sound more natural now. "Mister" may still be used more in very large cities. That is my experience, living in the USA.
I have a small problem, which isn't so small to me! I have all the way through been having trouble distinguishing some of the words of the male voice, especially between senor and senora. I suffer badly with Tinnitus and I suppose this might have something to do with it. It means that I keep getting marked down for not being able to hear something properly. I just wondered if anyone else had a similar problem?
I would urge students to click on the "light bulb" for the tips about what is being studied in that lesson, before doing the lesson.
I also recommend checking out thoughtco.com. The website holds a wealth of information about Spanish and English.
My thanks to the student who posted about thoughtco in a comment on a different subject.