"I write a letter to my friend."
Translation:Eu îi scriu o scrisoare prietenului meu.
Since you can drop the îi according to the multi choice answer, Can you also drop the Eu to make it even shorter? Would it still be understood normally as "Scriu o scrisoare prietenului meu."?
But when can you drop the short form of the dative pronouns? I thought they were mandatory...