singelply bellows

例句：

1. 1.The single bellows are used to blow air into the engine.
   单人鼓风机用来向发动机吹气。
2. 2. The old man was using a single bellows to keep warm in the cold weather.
   老人用单人鼓风机在寒冷的天气里取暖。
3. 3.The engineer had to replace the single bellows because it was worn out.
   工程师不得不更换单人鼓风机，因为它已经磨损了。