I have written a letter.改成否定句和一般疑问句?

I have written a letter.改成否定句和一般疑问句?
I have written a letter.改成否定句和一般疑问句?

I have written a letter.改成否定句和一般疑问句?
否定句： I haven't written a letter
一般疑问句： Have I written a letter?

否I have not written a letter
一般疑问：Have you written a letter?

i haven't written a letter.
Have i written a letter?

I have written a letter.
否定句: I haven't written a letter.
一般疑问句: Have I written a letter.