Lock : Key :: Door :
A. Handle
B. Frame
C. Knob
D. Room
Pen : Paper :: Knife :
A. Cut
B. Slice
C. Sharp
D. Tool
Moon : Orbit :: Satellite :
A. Space
B. Earth
C. Star
D. Planet
Brain : Thought :: Heart :
A. Emotion
B. Beat
C. Blood
D. Pump
Doctor : Patient :: Teacher :
A. Student
B. Classroom
C. Lesson
D. School
Ship : Ocean :: Plane :
A. Sky
B. Airport
C. Flight
D. Cloud
Bird : Nest :: Bee :
A. Hive
B. Honey
C. Flower
D. Swarm
Seed : Soil :: Fish :
A. Water
B. Pond
C. Lake
D. Ocean
Rain : Cloud :: Snow :
A. Cold
B. Winter
C. Freeze
D. Ice
Star : Galaxy :: Tree :
A. Forest
B. Branch
C. Leaf
D. Root