91. The conjunction δέ is postpositive - that is, it cannot stand first in its clause. Ordinarily it stands second.
Example (audio):
ὁ δοῦλος γινώσκει τὸν ἀπόστολον, ὁ δὲ ἀπόστολος βλέπει τὸν κύριον.
The servant knows the apostle and the apostle sees the Lord.