pillroller

例句：

1. 1. The engineer is the pell roller operator of the machine.
   这位工程师是机器的弹丸器操作员。
2. 2. The pell roller was designed to improve the accuracy of the projectiles.
   弹丸器的设计旨在提高弹丸的准确性。
3. 3. The pell roller was responsible for monitoring the operation of the machine.
   弹丸器负责监控机器的操作。