foreign body in urinary system

例句：

1. 1. The patient had a foreign body in his throat.
   病人喉咙里有异物。
2. 2.The doctor found a foreign body in the patient's bloodstream.
   医生在病人的血液中发现了异物。
3. 3. Foreign bodies can cause harm to the human body if not removed properly.
   如果不及时移除，异物可能会对人体造成伤害。