Has all that can be done been done?

Question

为什么用HAS 不用 HAVE
但是PEOPLE也是整体，动词用复数

Answer 1

先换成陈述句＝all that can be done has been done
主语＝all
定语＝that can be done
谓语＝has been done（被动）
转换成简单的主句＝all has been done
all 作为一个整体，集合名词所以用单数本回答被提问者采纳

Answer 2

这样说把all跟可数一起用的时候用复数
All animals have to eat in order to live.

单独使用的时候用单数
So long as he's happy - that's all that matters (= the most important thing).
All (= The only thing) I need is a roof over my head and a decent meal.

再如本例

参考资料：cambrige

Answer 3

他也不是复数呀
当然用has
比如 what he love is money
分析all that =what
该句换种说法
has what can be done been done
即

Answer 4

all修饰that.
that为主语。所以用has.
that本来就是一个代表单数的代词。如果要用复数的代词的话那只能是those
that的复数就是those了。
明白么？

Answer 5

意思:能做的都做了吗？
all:adj.全部的, 所有的, 整个的
that has been done
that 是指一个整体，所以用单数。