直肠

例句：

1. 1. He had a rectal exam to check his digestive system.
   他进行了直肠检查来检查他的消化系统。
2. 2. The patient was advised to drink plenty of water and eat fiber-rich foods to relieve constipation.
   病人被建议多喝水和吃富含纤维的食物来缓解便秘。
3. 3. The doctor performed a colonoscopy to investigate the possibility of colon cancer.
   医生进行了结肠镜检查以调查结肠癌的可能性。