impossible to subdue or defeat; cannot be overcome
 
        
                    
             
        
        
        
Using vivid words in a poetry or fiction is to create a mental image
        
                    
             
        
        
        
Hello!
"Quickly" is an adverb since it is describing the verb, "sped."
It answers the question "how did it speed?" - It sped <em>quickly</em>.