在英语语法从句中关于which与that的用法具体区别是什么？

1."Which"引导关系从句--就是用来补充说明，无论有没有都对主句的意思没有影响的从句。例如：
The
exhibition,
which
was
held
in
the
market
reserve,
contained
some
interesting
examples
of
contemporary
sculpture.
在这个例句中，作者假定读者知道所提及的展览会，所以展览地点只是一个补充说明。
2."That"引导的从句对事物起定义作用。例如：
The
exhibition
that
was
held
in
the
market
reserve
contained
some
interesting
examples
of
contemporary
sculpture.
这里，作者假定读者不知道提及的展览会，因此要告诉读者是哪个展览会："the
one
in
the
market
reserve"，(and
not
the
one
in
the
Botanic
Gardens,
or
the
one
in
the
Town
Hall)。
因为"That"引导的从具有定义的作用，把它们删掉会影响主句的意思。他们和所定义的词是一个完整的意思单元，因此中间没有用逗号分隔

which,
that
它们所代替的先行词是事物的名词或代词，在从句中可作主语、宾语等，例如：
A
prosperity
which
/
that
had
never
been
seen
before
appears
in
the
countryside.
农村出现了前所未有的繁荣。（which
/
that在句中作宾语）
The
package
(which
/
that)
you
are
carrying
is
about
to
come
unwrapped.
你拿的包快散了。(which
/
that在句中作宾语）

1.
that
可以代人，which
只能代物
2.在非限定性定语从句中只能用which
3.先行词有最高级，very,
all
,
only限定,或
something,
等不定代词时只能用that