that's the point of umbrellas, isn't it
What is the difference between wiesz and znasz?
wiedzieć - to have knowledge or information about something
znać - to be familiar with something/somebody
Wiedziec = Wissen, Znac = Kennen
Or, if you prefer, Wiedzieć = Savoir, Znać = connaître. Note also "Umieć", to know how to do something.
I just realized my previous comment is wrong... It is the other way around. Sorry
what is the rule for using commas?
It separates a dependent clause from the main one. Że is a word that introduces dependant clause, so comma before it is expected in most usual sentences.
List of words that introduce dependent clauses, and comma is usually expected can be found here
Is there some reason you can't translate "parasol" as "parasol"?
Polish "parasol" can be the one that covers you from rain and the one that covers you from sun, so yeah, it should work. Added.
wiesz = du vet
znasz = du kan
(pol - swe)