Respuesta :
It would be My teacher said my assignment was better, BUT I still got a B.
Answer:
This sentence can be fixed by adding the coordinating conjunction "but".
Explanation:
A coordinating conjunction is a conjunction that joins two similar constructions. In this case, it brings together two clauses (my teacher said my assignment was better/ I still got a B). The coordinating conjunction but is used to introduce a phrase or clause contrasting with what has already been mentioned. You can infer that the speaker expected a higher mark because the teacher told him/her that his/her assignment was better.