定语从句中先行词是all people时，关系词是用who还是that？

只能用THAT，见如下第一点：
限制性定语从句只能用that
的几种情况
1．当先行词是anything,
everything,
nothing
(something
除外),
few,
all,
none,
little,
some
等代词时，或者是由every,
any,
all,
some,
no,
little,
few,
much
等修饰时
(1)
Have
you
taken
down
everything
that
Mr.
Li
has
said?
(2)
There
seems
to
be
nothing
that
seems
impossible
for
him
in
the
world.
(3)
All
that
can
be
done
has
been
done.
(4)
There
is
little
that
I
can
do
for
you.
注意：当先行词指人时，偶尔也可以用who
(4)
Any
man
that/.who
has
a
sense
of
duty
won't
do
such
a
thing.
2.
当先行词被序数词修饰
(1)
The
first
place
that
they
visited
in
London
was
the
Big
Ben.
3.
当先行词被形容词最高级修饰时
(1)
This
is
the
best
film
that
I
have
seen.
4.
当形容词被the
very,
the
only修饰时
(1)
This
is
the
very
dictionary
that
I
want
to
buy,
(2)
After
the
fire
in
his
house,
the
old
car
is
the
only
thing
that
he
owned.
当先行词指人时，偶尔也可以用who
(3)
Wang
Hua
is
the
only
person
in
our
school
who
will
attend
the
meeting/
5.
当先行词前面有who,
which等疑问代词时
(1)
Who
is
the
man
that
is
standing
there?
(2)
Which
is
the
T-shirt
that
fits
me
most?
6.
当先行词既有人，也有动物或者物体时
(1)
Can
you
remember
the
scientist
and
his
theory
that
we
have
learned?

只能用THAT，见如下第一点：

限制性定语从句只能用that 的几种情况
1．当先行词是anything, everything, nothing (something 除外), few, all, none, little, some 等代词时，或者是由every, any, all, some, no, little, few, much 等修饰时
(1) Have you taken down everything that Mr. Li has said?
(2) There seems to be nothing that seems impossible for him in the world.
(3) All that can be done has been done.
(4) There is little that I can do for you.
注意：当先行词指人时，偶尔也可以用who
(4) Any man that/.who has a sense of duty won't do such a thing.
2. 当先行词被序数词修饰
(1) The first place that they visited in London was the Big Ben.
3. 当先行词被形容词最高级修饰时
(1) This is the best film that I have seen.
4. 当形容词被the very, the only修饰时
(1) This is the very dictionary that I want to buy,
(2) After the fire in his house, the old car is the only thing that he owned.
当先行词指人时，偶尔也可以用who
(3) Wang Hua is the only person in our school who will attend the meeting/
5. 当先行词前面有who, which等疑问代词时
(1) Who is the man that is standing there?
(2) Which is the T-shirt that fits me most?
6. 当先行词既有人，也有动物或者物体时
(1) Can you remember the scientist and his theory that we have learned?