You have 88.
You opponet has KK.
The flop is 2-10-A
You have two outs. There are 45 unseen cards.
You have 45:2 odds to make your hand...or 22.5:1.
So, if you are playing correctly, you should only call a bet if you are getting these kind of pot odds
($10 bet into a $300 pot (30:1 odds))
Most of the time you use pot odds on draws... The # of outs you have against the number of unseens cards.
Get a poker book, most of them explain this in detail.