Our father is Abraham (ο πατηρ ημων Αβρααμ εστιν). They saw the implication and tried to counter it by repeating their claim in verse John 8:33 which was true so far as physical descent went as Jesus had admitted (verse John 8:37).

If ye were (ε εστε). Strictly, "if ye are" as ye claim, a condition of the first class assumed to be true.

Ye would do (εποιειτε αν). Read by C L N and a corrector of Aleph while W omits αν. This makes a mixed condition (protasis of the first class, apodosis of the second. See Robertson, Grammar, p. 1022). But B reads ποιειτε like the Sin. Syriac which has to be treated as imperative (so Westcott and Hort).