Answer:
AB, CD
Step-by-step explanation:
Skew lines do not lie in the same plane, and do not intersect. One such pair is AB and CD.
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Additional comment
Any of the lines, and any of the lines that intersect its diagonally-opposite edge will be skew lines.
For example, the opposite edge to line BC is line EG. Lines that intersect EG are ED, EF, GA, GH. All of those four lines are skew with respect to line BC.
