joint between three members

例句：

1. 1. The joint between the twopieces of wood is loose.
   两块木头之间的接合处松动了。
2. 2. Thescientist used a special toolto join the broken pieces together.
   科学家用一种特殊的工具将断裂的部分连接起来。
3. 3. The car's engine hasa joint in the middle that needs tobe replaced.
   汽车的发动机中间有一个接头需要更换。