幽门

例句：

1. 1. The patient's stomach was full of pain, and the doctor had to operate on him urgently.
   病人的胃痛得厉害，医生不得不紧急为他做手术。
2. 2.The mystery of the ancient tomb has puzzled many scholars for centuries.
   这个古墓的谜团让很多学者困惑了几个世纪。
3. 3. The problem of pollution in the city is becoming more and more serious.
   城市污染问题越来越严重了。