a dilatation of blood vessels的用法和樣例：
例句
- A good warm-up dilates your blood vessels, ensuring that your muscles are well supplied with oxygen.
充分的熱身運動可以使血管擴張，保證肌肉得到充足的氧氣供給。 - During an attack, the blood vessels in the brain dilate and then draw together with stimulation of nerve endings near the affected blood vessels.
當偏頭痛發作，大腦中的血管擴張，然後由於神經的刺激而收縮，由此影響血管。
