Tag question

[fadysandy]

I've read this sentence, but I don't know why the writer used 'did we'
In the past the Nile flooded, so we didn't need chemical fertilizers, did we?
May be the writer is mistaken!

 

[Rover_KE]

No – it's fine. That's the standard way to ask a tag question. Negative becomes positive and vice versa.

I'ts hot, isn't it?
You're rich, aren't you?
It's not fair, is it?
You won't give away my secret, will you?

 

[fadysandy]

I think 'Tag question' should be based on subordinate clause.
It should be ' In the past the Nile flooded, so we didn't need chemical fertilizers, didn't it?'
Am I correct?:shock:

 

[Rover_KE]

No.

In the past the Nile flooded, didn't it? We didn't need chemical fertilizers, did we?

 

[fadysandy]

So we can say 'I’ll help you if you ask, won't I? '

 

[Rover_KE]

Yes.

 

[Tdol]

So we can say 'I’ll help you if you ask, won't I? '

Yes, but you're asking about the help. In the first example, you're asking about fertilizers and not whether the Nile flooded- you want to emphasise that fertilizer wasn't necessary.