The line in Mulan's poem that expresses the tragic and heroic war is

The tragic and heroic poems of war:

The fresh air spreads to the golden watch, and the cold light shines on the iron clothes. A general will die in a hundred battles, and a strong man will return after ten years.

Meaning:

Marching thousands of miles to fight on the battlefield, crossing passes and mountains as quickly as flying over them. The cold wind from the north was mixed with the sound of the watch, and the cold moonlight reflected the armored shirts of the soldiers. The soldiers went through countless life-and-death battles, some died on the battlefield, and some returned victorious.