plz explain them to me, thanks you very much

Try this for size:

An 'absolute advantage' is when there is absolutely no argument;

A 'Comparative Advantage' is when the advantage is much more debatable.

(Only guessing.)

http://www.bized.ac.uk/virtual/dc/trade/theory/th2.htm

IMO Hechsher and Ohlin should have been drowned at birth

Let's use two roomates as an example here, Al and Bert.  Let's say Al
can wash the dishes in 10 minutes and clean the house in 30 minutes. 
Let's say Bert can wash the dishes in 15 minutes and clean the house
in 2 hours.  Al has an absolute advantage in both of these chores. 
But even when one person has an across the board absolute advantage,
it turns out to be beneficial to both people if Al only cleans the
house and Bert only washes dishes (assuming they can agree on
compensation for the differences in value each one brings to the
bargain).  Al has a comparative advantage in cleaning the house and
Bert has a comparative advantage in washing dishes (the best use of
Al's time is cleaning the house and Bert's best use of time is washing
dishes).