What are the experiences/lesson you've learned from the past year 2020

To be grateful of what I have and not what I need,

Appreciate those who work hard, and are not often recognized

Be thankful for those I have

And above all to just be more aware of what's happening

the following what exactly?

. a function is a relation in which each input has only one output. in the relation , y is a function of x, because for each input x (1, 2, 3, or 0), there is only one output y. x is not a function of y, because the input y = 3 has multiple outputs: x = 1 and x = 2.