"She reads your books."
Translation:Hon läser dina böcker.
I'm having trouble remembering when to use an -in possessive versus -ina. Any rules of thumb?
Din is for singular en-words, ditt for singular ett-words, and dina is for plural. Böcker is plural (many books), so you use dina.
If "your" refers to one person, use din/ditt/dina, if "your" refers to multiple people, use er/ert/era
Depends on the number. In English you/your/yours may be referred to both singular and plural. In other languages, like Swedish, there are two different forms.
I selected "dina" here but it says the correct answer is era. I don't understand why the translation also uses dina if it's incorrect.
Two times on questions like this I selected one of the right answers and it marked it as incorrect? Just a bug?