why is ξέρετε wrong??

Will this translation work: "Ξέρεις αν αυτός είναι πρόκειται να φυγει αύριο;"

Ξέρετε is still marked wrong. Needs adding in?

"Ξέρεις αν αυτός πρόκειται να φύγη αύριο;" The inclusion of thw word "αυτός" shouldn't preclude the translation from being accepted. It is optional to include this word in the Greek translation, and should be accepted as an alternative translation.

Ξέρεις αν πρόκειται να φύγει αύριο αυτός; is marked as wrong. I don't know why