英语选择题，为什么选b不选c?

Question

英语选择题，为什么选b不选c?You'd better to choose someone___ you think____ kind and friendly to help you.
A. whom,to be B.who,is C.that ,is

Answer 1

句子You'd better后面不应该有to， 其次这题B 和 C都是可以的。传统上认为现行词是人的时候不用that，只用who， 但现代英语无论语法书还是实际应用， that和who都是可以的，who用的更多一些。

福勒现代英语用法里对此问题这样解释：
Fowler's Modern English Usage says: ‘That can also replace who (or whom), especially when the reference is non-specific, as in The person that I saw was definitely a woman.’追答

另外这不是插入语，you think 自带了一个宾语从句，而that/who you think...作someone的定语从句。

Answer 2

这是一道定语从句题，先行词为someone 是人，所以用who 不可以用that

其实这个句子是You'd better to choose  someone who is kind and friendly to help you. you think是插入语。

追问

that不是也可以指人吗？

追答

对呀，但是who更合适