[oi)=sqa] means [the same as] oi)=das. It is also pronounced without the sigma, but with the sigma (oi)=sqas) sometimes either for the sake of meter or in order to keep a consonant from clashing.[1]
Sophocles [writes]: "you know [that you are] about to do what." Instead of poih/seis, "you will do," in Attic.[2]
And elsewhere: "you know that some clearing themselves in the law-courts or persuaded by some single misfortune have become philosophers merely from an oath or vow to God in the Platonic manner; a shadow would outstrip such men in speaking what is right."[3]
They also say e)/coisqa "you know well". Sophocles [writes]: "you also know from being present, with no one of his friends as guide, but himself leading all of us ..."[4]