ok, i will. thank you very much!! from where is this knowledg??
and what should i do in this part? :

You're welcome. That's a common practice by different teachers, my current and the one before both gave me that resource for practicing and solving this type of problems, as well as other teachers from friends, they all apply that way of practicing.
For this second part you mentioned, it's the same as in the others, just with the rhythm that's marked.
Also, what the others have been saying is a good help. There are many ways for solving everything in piano, and it's always better that you apply as many resources as you can and know. You can even invent one, just make sure it solves the music, and that it doesn't hurt you

. Try also practicing with dotted rhythms, and then dotted rhythms while playing stacato the triplet notes, or in other words, not only apply every resource you know, but also, combine every resource you can, that will give you a new resource.
