THAT引导定语从句时必须在从句中做成分吗?

题目

THAT引导定语从句时必须在从句中做成分吗?

答案

是的
that在引导定语从句是可做宾语和主语
如：I found the key that I lost.(that在从句中做宾语并可省略)
The bridge that was built in 1556 has been rebuilt now.(that在从句中做主语并不能省略)