Question

英语问题谢谢

Answer 1

i
will
hire
the
man.是一个完整的句子。则____they
say
is
a
good
English
speaker是一个定语从句。
则who的作用就是做一个定语从句的先行词，这个定语从句修饰the
man
即who=the
man做主语，后一个句子即是they
say
the
man
is
a
good
english
speaker.

Answer 2

I
will
hire
the
man____they
say
is
a
good
English
speaker.

将句子简化一下你就明白了，

I
will
hire
the
man,
who
is
a
good
English
speaker.
这个被填入的词要做后半句的主语，只能选WHO

Answer 3

因为WHO做主语·这里缺少的是主语·修饰后面的they
say
is
a
good
English
speaker
WHOM只能修饰宾语