This is the second time she has been here, isn't it?

English as a Second Language English Vocabulary, Grammar and Idioms
1

This is the second time she has been here, isn’t it?

Please could anyone analyse concerning clauses,that’s which one is main clause and…?

Thanks…

2

Well, this is just a sentence followed by a question tag.[YSaerTTEW443543]

TOEIC listening, question-response: Why don’t you try Home Warehouse?[YSaerTTEW443543]

3

As Torsten said, this is a sentence with a question tag (isn’t it?). You can still analyse it as follows:

This is the second time - Main Clause
(that) she has been here - Subordinate Clause

The tag, in my opinion, may also be called another Main Clause.

Or, if you restructure the sentence like ‘Isn’t this the second time she has been here?’, you will find that ‘Isn’t this the second time’ is the Main Clause.