蛭

例句：

1. 1. The doctor advised me to avoid swimming in the river after my operation.
   手术后，医生建议我避免在河里游泳。
2. 2. The leeches were sucking blood from my wound.
   蚂蟥正在从我的伤口吸血。
3. 3. The water snail is a common sight in many rivers and lakes.
   水蜗牛是许多河流和湖泊中常见的一种生物。