"Je dois changer de lentilles de contact."
Translation:I need to change my contact lenses.
Where is the "my" in the french phrase ?? I wrote "I must change contact lenses", why is that translation incorrect?
In French it's implied that it's for the person mentioned in the subject, unless the sentence makes it specific it's for someone else. In English we usually respecify that it's for the person in the subject.
My answer "I must change my contact lenses" was not accepted, despite being accepted in previous translations/conjugations of "devoir". Is there much of difference (in French) between saying "I must", "I have to", or "I need to"?
There are some difference:
To be concise :
"devoir + infinitif" = obligation or high need
"falloir + infinitif" or "falloir que + subjonctif" = obligation or high need
"avoir besoin de" = need
Here "Je dois changer de lentilles de contact" it's not an obligation, it's not a duty or nobody force me to change them. It's a need, an important need but a need and there is no obligation to do that so "I need" is the best translation.