修改病句Who are they They are doctors 哪错了?

以答句来看，如果问的是职业就不该用who提问……

问职业用what不用who

本句式问职业的所以Who are they 不对用 what do they do ?

问职业要用这么说:你们是做什么的? 而不能说:你们是谁?
what do they do?
they are doctor

What are they? What do they do?
They are doctors.

What are they？
They are doctor.

本题实际可以有两种理解
第一种是问职业，从汉语角度来说是: 他们是做什么的? 回答是：他们是医生
What do they do?或者What are they?
They are doctors.
第二种理解是问话人不知道那些人是谁或者是想知道那些人是谁，此时可以用who来提问，但回答时一般要比较确切些（说出名字或者限定是哪里的人）。此种场景下可以这样来说：
Who are they?
They are Mike, Tom and Nancy, the doctors from No.1 Hospital.

从一问一答可以看出,前句是对职业的提问.对职业提问一般不用who,可用what are they?或者what do they do?或者是what are their jobs?
Who are they 意为他们是谁,他们都有谁等等,也可以表示询问职业,但很少用.通常回答是如:（they are Jack,Tom and Jim）、（they are teachers of our Middle school）.之类.

学英语不是要按汉语的思维进行翻译的，要知道英语的习惯，学会地道的英语。What do they do?Or What are they?