脉络

例句：

1. 1. The scientiststudied the blood vessels in the human bodyto understand how they work.
   这位科学家研究了人体血管的工作原理。
2. 2. Thedoctor examined her for anysigns of a vascular problem.
   医生检查了她是否有血管问题的迹象。
3. 3.The researcher found that the veinsin the skin were responsible for carrying oxygenated blood back to the heart.
   研究者发现皮肤中的静脉负责将富含氧气的血液输送回心脏。