1. In general, it's better to undo the problem by adding more iron-rich foods to the diet, because iron supplements can have serious shortcomings.
    一般说来，解决问题的最好方法是在食谱中增加含铁丰富的食物，因为铁离子补剂可能存在严重缺陷。"

2. Fatigue and poor performance may begin to appear in the second stage of deficiency, when not enough iron is present to form the molecules of blood protein that transport oxygen to the working muscles.
    到了缺铁的第二阶段，就会出现疲倦和力不从心，此时体内已没有足够的铁来形成血蛋白分子，将氧输至运动着的肌肉。