1. Lines AB and CD are both perpendicular to the line EF, then AB || CD (parallel).
2. The relation between lines CD and GH cannot be defined, because the diagram doesn't contain any information about angles at which these lines intersect (or any data about parallelity GH to EF or IJ).
3. The relation between lines AB and GH cannot be defined, because the diagram doesn't contain any information about angles at which these lines intersect (or any data about parallelity GH to EF or IJ).
4. Lines IJ and CD are perpendicular (IJ⊥CD) because they intersect each other at right angle.