Kate(can not) read and write until she was six

Kate could not read and write until she was six.

Couldn’t Kate read and write until she was six?

Who could not read and write until she was six?

What could Kate do until she was six?

How long couldn’t Kate read and write?

Couldn’t Kate or couldn’t Mary read and write until she was six?

Couldn’t Kate read and write or sing until she was six?

Couldn’t Kate read and write until she was six or seven?

Kate could not read and write until she was six, could she?