Comparison between there and demonstrative pronouns
Who claim there is a subject \ question tag ?
Though many books apparently tell that ( there or here ) is never the subject, but the noun that follows, some people still stick in their minds agreeing ( there ) = subject and their evidence is that ( there) = the subject in the question tag ?
The idea is not so, it is just special rule (( The matter is not only with there )) ?
Here are examples :
1- There is a cow , isn't there ?
2- This is a cow , isn't it ? Why we don't say [isn't this] ?
3- That is a cow, isn't it? Why we don't say [isn't that]?
4- These are cows, aren't they ? Why we don't say [ aren't these ] ?
5- Those are cows, aren't they ? And not aren't those ?
Consider the following examples :
This is yours, isn’t it? Not isn't this
Those don't work, do they? Those 100 % = subject
However, we don't say : Do those \ are those
Only one thing I want to add; to say dummy or real this is not the case. If it is beyond the grammar which is correct grammar and which is incorrect. There are always exceptions with the English language (( People, since ancient time, have used the language so )) The photo below clears it