Advertising plays an important role in modern life.

Currently, a huge amount of advertisements are shown while we are watching television, walking down the street(ed-note:"walking on the street" would also work) and(ed-note: since you''re listing non-mutually-exclusive possibilities, "and" is the better choice, though "or" could work as well) even when we are surfing the web. In some cases they are entertaining, but in others can result in being too annoying.
On the one hand, advertisements are necessary so that companies can promote their products and, consequently, these can sell(ed-note: I'd re-write as, "...so that companies can promote and, consequently, sell their products."). Although, it is true that sometimes companies are not aware that advertising the same product many times could bore consumers(ed-note: you seem to have some issues with verbs?). For instance, one product which is advertised in many places during a short period of time, consumers finish tiring of it and even, avoid it.(ed-note: this sentence is, in this context, unnecessary. It's essentially identical to the previous one, but re-worded.)
On the other hand, people need to know which product to choose between all that's(ed-note: 1 - "all" is singular, technically, so "all that is." 2 - You're not Cockney, don't use "what" for "that.";)) on the market, and so advertisements are not only necessary, but also absolutely useful. The reason is that to buy a particular product, people prefer knowing about it beforehand, and that is shown by advertisements.
In conclusion, I think advertisements are extremely important in(ed-note: "to" may be more appropriate here. Maybe.) our society in order to get to know products and sell them(ed-note: notice how you went from consumer POV to the corporate one? Don't do that.) in spite of them annoying us on occasion.

They're writing a report, I'd say; it's a direct response, intended (I assume) only for a select cadre of people. In this case, military personnel writing about what they've experienced, and only the military'll read it. So, a report.

Title: "If anyone/someone could correct the false grammar?" or, "Can anyone/someone correct the grammar issues?" She came to the hospital complaining of both legs swelling. It started one month ago with a gradual and progressive course, increasing during the day and combined with swollen eyes in the morning soon after she woke up. The edema started in her eyes then spread to/developed in her lower limbs, and it is most probably a renal edema. Neither fever nor weight-loss were present. Other symptoms include not being able to open her eyes when exposed to direct light or to the sun, *with 24 flushy cheek redness.* This was one way of correcting it. The asterisks enclose the part of the paragraph that I don't understand; what's "24 flushy cheek redness" mean? Otherwise, not to bad. Your issues: tone (this seems to be some kind of medical report; keep a distance between the events you describe and yourself) and sentence structure (especially concerning tense; you go from present to past within the same sentence, and that's a big no-no). Otherwise, good work.

Sorry to disappoint, but I can't correct you. The sentence has no issues.

I actually may need an example. I don't think I've ever heard "related with" used - you have relations with someone, you're related to someone, something is related to something, etc. So the difference is that one is (as far as I can tell) wrong. You'd still be understood though.

What Kris said, you're golden. "Sentence", though.