"Even though" and "even if"

Well done/buen hecho. I changed the second sentence to agree with the plural. 

"Even though" and "even if"

Good morning Diego. This is a great question! Basically, you would use "even if" when you are not sure of the outcome yet, and you would use "even though" when you know what the outcome is or may be. Using your examples: Mexico will win the World Cup even if they don't play their best game. - This implies that we don't know if they will play their best game or not. If you said, "even though they won't play their best game" it implies that we know they won't play well in this match. -Spanish young people are is going abroad to look for a better jobs even though they already have some one here. -Even though is used perfectly in this context and implies that people who are already employed in Spain are still seeking work abroad. You could also say "even if they already have a job here" which would just change the meaning to imply that people both employed and unemployed are looking for jobs abroad. -I'm going to buy a sailing boat even if my wife doesn't allow me. - Saying "even if my wife doesn't allow me" implies that you don't know yet if she will let you. If you said "even though she won't allow,me", it means,you already know she won't allow you to buy it. -You must read as many books as you can even if you can't pay them. - In this sentence, you may want to replace the word "pay" with "afford". You pay a person, not a book. "Even if you can't afford" implies you don't know if the person can afford them or not. "Even though you can not afford them" means you know the person does not have enough money to buy many books.