I think this means:
If it's possible for a human being to do something, don't just say that he can't, just let him try, give him a chance.
To make it parallel I would say to put it in this format: We can’t go back; to go forward is our only option. This makes the verbs the same.
Suspense; <span>a state of feeling excited or anxious uncertainty about what might happen.
Look at google for more information</span>
-nature: it is the men's protection and shelter but is also portrayed as a living thing that is being destroyed just like them
-comradeship: Possibly the most beneficial thing a soldier can have when it comes to survival. Paul, Kat, and Kropp are very close. At one point Paul uses his friends to help him move forward. "<span>At once a new warmth flows through me. These voices, these few quiet words, these footsteps in the trench behind me recall me at a bound from the terrible loneliness and fear of death by which I had been almost destroyed. They are more to me than life, these voices, they are more than motherliness and more than fear; they are the strongest, most comforting thing there is anywhere: they are the voices of my comrades.(ch. 9. p. 216)
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the horrors of war: constant terror, violence, exposure to diseases, vermin infested living areas, technology designed only to kill with less effort, and death ( almost every character is dead by the end of the story)
the effects of war: men subject to extreme physical danger and terrifying events which in turn affect their mind. Paul forgets his past and loses his ability to speak to his family.
franz's boots: represent the cheapness of human life. They are passed from soldier to soldier as each one dies. As Kemmerich lays dying Muller is already moving to take them. The war has forced them to value the items over their fallen companions
butterflies: represent nature's beauty. A soldier lets his guard down to admire it because it reminds him of the beauty he used to know and is shot.
potato cakes: represent sacrifice. Paul's mother and sister are don't have much to eat, but give up some of what they have to Paul if it means he will have a bit of comfort.
Well, think about a very important, special change that happened in your life. Make sure to be specific though.