Geometry

Question Analysis：
This question examines the properties of reflection over y = x, especially the effect on shape, orientation, and position.

Key Concept Explanation:
Reflection over y = x:
Swaps x and y
Preserves size and shape
Changes orientation (it’s a flip, not a rotation or slide)

Step-by-Step Solution：
A. ✅ Swap coordinates — fundamental to this reflection
B. ❌ Not a rotation — figure flips, not spins
C. ✅ Orientation changes — left/right becomes up/down in some cases
D. ✅ Size and shape stay the same (rigid transformation)
E. ❌ Not a translation — nothing is “slid”

Common Mistakes：
Mixing up reflection with rotation o...