Answer:

DEES

Answer	Crossword Clue
DEES	Poor grades
DEES	Bad grades
DEES	Wedding couple?

DEES	Sandra and Ruby
DEES	Ruby and Sandra
DEES	Odd couple?
DEES	Bad marks
DEES	Deadhead's trio
DEES	"Disco Duck" writer Rick
DEES	They're just passing
DEES	Barely passing grades

DEES	GPA reducers, probably
DEES	Low marks
DEES	Add ends?
DEES	Low grades
DEES	Poor showings in class
DEES	They barely pass
DEES	Near-failing grades
DEES	They won't get you on the dean's list

DEES	Radio DJ Rick
DEES	Substandard marks
DEES	GPA spoilers
DEES	They're barely passing
DEES	Unenviable grades
DEES	They're below average
DEES	They're worth 1.0
DEES	Unsatisfactory grades

DEES	Below-average grades
DEES	Odd couple, or dead ends?
DEES	Deejay Rick of "Disco Duck" fame
DEES	Two in the middle of middle
DEES	Deejay Rick
DEES	Rick of "Disco Duck" fame
DEES	Middle middle?
DEES	Dead ends?

DEES	"Disco Duck" singer Rick
DEES	Two-pointers in Scrabble
DEES	"Middle" middle?
DEES	Inferior marks
DEES	Kiki and Sandra