there's no such thing,such和thing之间为何不加冠词,

这是专四语法.
there is no such thing.这句是 简化版本的高考题.
这句话的完整版本,专四考试题是：
there is no such thing as ················难点是as 后面的东西.
比如世界上没有鬼怪这一说：
there is no such as a ghost exists.
注意这句话里面的 a ghost,有 冠词 a
再比如：没有水可以转化为核武器这一说：
there is no such thing as water can be turned into nuclear power.
此处注意 water 前面无冠词.
次句话难点不是 no such thing .
there is no such thing 只是一个 基础.记住即可.
难点是后面.
如果 as 后面跟得是 可数,那么要加 a
如果 为 不可数.不加a .