The Adjective, by being deprived of the Article, has ceased to be an attribute, and has become a predicate.
But the answer key to exercise 1 translates the following:
I see many swans, which are bright and white.
ὁρῶ πολλοὺς κύκνους, οἱ λαμπροὶ ἐισι καὶ λευκοί.
Should not it be κύκνους τοὺς πολλοὺς?
And the same here, the answer key translates:
Perhaps there is a bad disease ...