I'm sorry, I'm so sorry- but I think you did poorly.
There are several surface level errors and I think you did a poor job of analyzing the original statement.
"...by studying some major cities of a society, one is able to understand its most important characteristics." The use of the word "some" implies that only a few of the major cities are studied- when the statement says "it's major cities" not "a few of" or "some of" or "one or two".
You also wrongly assume that only contemporary societies are on topic- what pre-history societies?
There are places where language fails here- "almost inconceivable" weak, what are you trying to say?
"not a very indicator" simple typo, or a reflection of writing skills- I'm not the ETS but it would be hard to see past it.
" interacting with a society in person" as opposed to interacting via teleconference? not sure what you mean by in person.
"majorly populated cities such as Beijing lived very comfortably with fancy cars" first verb tense, people lived- do they know longer live there? Secondly, drop the very. Adding words like "very" only dilutes your essay. Thirdly- do they live with the fancy cars or are the fancy cars a sign of "very comfortable" living- the way it is written it sounds like they live comfortably despite sharing their homes with fancy cars.
"poor people who commute more than an hour by bicycles." they commute by bicycle not bicycles... unless they use more than 1 to get where they're going.
"In fact, cycling to work is more common than one would think since there are more than 3 billions of bicycles sold each year" A. The way this is written you are saying cycling to work is more common because there are a bunch of bicycles sold each year. Do you see the flaw in the logic here? Perhaps it is reversed and a bunch of bicycles are sold each year BECAUSE a lot of people cycle to work. B. "more than 3 billions of bicycles" Certainly you mean there are more than "3 billion bicycles" not 3 billions.
Need I go on?
The good news? You can always practice and I'm willing to give you a few pointers here and even point you in the direction of some very nice writing handbooks.