Answer:
I believe it means that once you rech your fullest potential, you can make the imposible, posible. 
It could also mean that who you are now, you used to think was impossible.
Explanation: 
Theses are the two posible meaning I came up with by looking at it two different ways.  
 
        
             
        
        
        
Answer:
Rita Dove
I hope this helps you!
Have a great rest of your day!! : )
 
        
             
        
        
        
I think it is  But our revived spirits were not to be damped by difficulties on the last stage of the journey, and we camped cheerfully for breakfast.
        
             
        
        
        
A) Yesterday Sydney mailed the short story from the post office located near the school.