以下为曹老师的讲解原文：
Anna is a vegetarian, which I consider no one else in our family.（非限归表）
consider应改为think。no one else后应该加to be.
She is the perfect accountant，which I don’t consider her predecessor. （非限归表）此句为错句。句末应该加to be.
I don't think it is the good investment (that) they consider it.（确表）
宾补不可以为确认性的。句末必须加to be，让不定式作宾补。
我的疑问：以上几个句子为什么必须加to be?
