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): A simple harmonic oscillator is an uncomplicated type of simple harmonic oscillator, which consists of an object attached to a spring sliding on a frictionless surface.