Если Вам нужно в настоящем времени,тогда:
I wonder what the most important industrial cities are in England.
I wonder what Stafford-upon-Avon is famous for.
I wonder what the main attractions of the North of England are.
I wonder what you кnow about Hadrian's Wall.
Если Вам нужно в прошедшем времени тогда:
I wondered what the most important industrial cities were in England.
I wondered what Stafford-upon-Avon was famous for.
I wondered what the main attractions of the North of England were.
I wondered what you кnew about Hadrian's Wall.