Originally Posted by sflor

Hi!

For this sentence "do not be ungrateful when you receive a gift" we can say "não cuspas no prato em que comeste" (literaly, do not spit on the plate that you ate).

For the real proverb you added, I would say it is "A cavalo dado não se olha o dente" which I guess it hasn´t got the same meaning of the one that I mention above...

Ciao,

sflor