Question

in the holidays 和 on holiday两者的区别？

Answer 1

in holiday 泛指放假，但说话人说话的时候并不在放假。
如，i'd like to stay with my families in holiday.

in the holiday 指特定的假期，根据上文的延续。
如，Christmas is a spcial holiday in western countries. In the holiday, people usually stay with their families.

on holiday 处于放假的状态
如，i'm on holiday now.类似有on duty 上班中
帮你造了几句话,你可以通过理解句意来看区别,希望对你有用
on the holiday:
A few more traveller's cheques may come in handy on the holiday.
多带几张旅行支票，度假时会有用的。
in the holiday:
we (enjoy ourselves) in the holidays.
In the holiday season one finds the trains unpleasantly full of people.
节日期间，人们可以看到火车上拥挤不堪，人满为患。

如果你前面曾经提起过某个节日，而现在针对这个节日说on，就要用on the holiday,特指在这个节日。否则，用on holiday.

Answer 2

in
the
holidays
在假日里；(be）on
holiday
在度假。

Answer 3

holiday与holidays的联系
1）holiday的基本意思是“假期”,指源于宗教的“节日,假日”,也可指不用去上班、上学等的“休假日”“假期”,还可指“出外度假时期”.其单数形式指包括含一天或一次的假期,复数形式指一次以上或一天以上的假期.
2）holiday作“休假期”解时常用于复数形式,是英国用法.
3）holidays如作整体看待,可作单数处理.
4）有时holiday可以不包括星期日.例如:this
store
has
no
business
on
sundays
and
holidays.这个商店在星期日及假日停止营业.
介词搭配
during
one's
holidays
在假期中
be
out
for
a
holiday
外出度假
on
holiday（s）
度假
例句：
generally
speaking,the
parks
are
full
on
holidays.
一般来说,假日里公园都挤满人.
she
is
on
holiday
in
france.
她在法国度假.