sentinel antibody

例句：

1. 1.The sentinel guarded the gate all night.
   哨兵整夜守卫着大门。
2. 2. He was a sentinel on the battlefield.
   他在战场上担任哨兵。
3. 3.The sentinel kept watch over the castle walls.
   哨兵在城堡的城墙上站岗。