Sadness and Happines

Before reading this story, my first question is that what the meaning of the title is. After reading, I learn that the butterfly refers to the happiness when the flit gun man was absorbed in squirting others and the tank refers to the sadness which is the ending of death. On the one hand, the background of this story is war. As a matter of fact, tank was the symbol of cruel war and the butterfly was exactly the symbol of slight happiness of the soldiers. Obviously, the power of butterfly is far less than that of tank, which hints the sad ending in the story. Therefore, we are all dedicated confronted with war no matter an individual or a country. On the other hand, I believe that the author intended to tell us that the life is full of sadness and happiness. Perhaps we are happy now and next second we are lost in sadness and sufferings. So we have to adapted to life and reality to be a rational and emotional person.