Why are you always arguing with each other? 你俩为什么老是吵个不休？
- The two companies are in competition with each other.
- Children can be very cruel to each other.
- It was one of those parties where nobody really knew each other.
- The boys were splashing about and ducking each other in the pool.
- Rachel and Fi have had a big argument and now they're not speaking to each other.