He has changed a lot. He is not what he was used to be.去掉 was used to 表示今昔对比

问题补充：

He has changed a lot. He is not what he was used to be.去掉 was，used to 表示今昔对比

答案：

(答案→)去掉 was，used to 表示今昔对比

解析：be used to 表示“习惯于”。