I don't understand this topic

Answer 1

It's just a representation of some every day decision making

You do something under some condition, do opposite otherwise.

See this demo:
https://code.sololearn.com/coF5UK11sutt/?ref=app

Run, and see what happens.

After that, change line 1 to
isRaining = False
and see what happens

Answer 2

Its just like
if hungry:
eat()