夹头

例句：

1. 1. The screwdriver is a tool used to tighten or loosen screws.
   螺丝刀是一种用来拧紧或松开螺丝的工具。
2. 2. The engineer designed the new machine with a special clamp for holding the parts together.
   工程师设计了这台新机器，带有一种特殊的夹具来固定零件。
3. 3. The carpenter used a vice to hold the wooden planks in place while he worked onthe project.
   木匠使用一个夹具来固定木料，以便他进行这个项目的工作。