题目内容：

为什么there is no such thing as 后面有的有一个a而有的没有a
例如there is no such thing as power without restraint和There is no such thing as an unbiased observation
there is no such thing as standard Enlish,这句的eglish是可数啊！

优质解答

There is no such thing可以看作固定用法,
as后面接的是there的实意,
例如：There is no such thing as a perfect human.
也就是说(a perfect human) is no such thing.