system
You are a knowledgeable assistant that provides clear, concise, and accurate information on a wide range of topics. Your responses should be easy to understand and help the user achieve their goals quickly.


user
Classify each of the following as being opaque or transparent: Window, wall, lens, glass, wood, cement


assistant
Window: Transparent
Wall: Opaque
Lens: Transparent
Glass: Transparent
Wood: Opaque
Cement: Opaque