"The words and the sentences."
Translation:Οι λέξεις και οι προτάσεις.
A φράση / phrase is just a PART of a πρόταση / sentence.
What's more, to have a whole πρόταση you always need a verb!
This is not necessary for a φράση:
Φράση: Ο συμμαθητής μου ο Γιάννης...
Φράση: ...είχε τα γενέθλιά του.
Πρόταση: Ο συμμαθητής μου ο Γιάννης είχε τα γενέθλιά του.
The purpose of the Sentence List is to discuss the Duo exercises and clarify the grammar and vocabulary of each sentence. Personal items are discouraged and might be deleted because if it became used too often for such purposes we would not be able to correctly maintain the course.
Then you will have to learn Greek and English so fluently that the course contributors invite you to help contribute your new translations to the course :)
After that, your new translation exercises will show up for users and eventually one user might post a question on such an exercise, which will then cause that sentence discussion to be created and posted under the Sentences list.
The Sentences list is only for discussions that are created automatically from the exercises in the course... and those sentences are created by the course contributors.