Vena saphena magna

例句：

1. 1. The veins carry blood away from the heart to the lungs.
   静脉将血液从心脏输送到肺部。
2. 2.The veins are responsible for transporting nutrients and oxygen throughout the body.
   静脉负责将营养物质和氧气输送到整个身体。
3. 3.The veins are visible under the skin, but they are not as prominent as arteries.
   静脉在皮肤下可见，但不如动脉显眼。