too little iron

例句：

1. 1. The car engine needsmore oil than usual to keep it runningsmoothly.
   这辆车的引擎需要更多的油来保持顺畅运行。
2. 2. We need more ironto make the bridge stronger.
   我们需要更多的铁来使桥梁更坚固。
3. 3. Thedoctor prescribed a higher doseof iron for her anemiatreatment.
   医生给她开了更高剂量的铁来治疗贫血症。