Task: Paraphrasing
Input (English): Question: An object attached to a spring sliding on a frictionless surface is an uncomplicated type of what device? 
Answer: simple harmonic oscillator. 
Sentence: An object attached to a spring sliding on a frictionless surface is an uncomplicated type of simple harmonic oscillator.
Output (English): You can have any object slide on a frictionless surface, but once it is attached to a spring, it becomes an uncomplicated simple harmonic oscillator.