1 . -- I didn't realize how popular the restaurant was until I made a reservation the other day.
-- I beg your pardon, but when __________?

A．was you realized it

B．it was that you realized it

C．you realized it

D．was it that you realized it

2 . It was not until the 18th century that man realized that the whole of the brain was involved in the working of the mind，　　　　？

A．was it

B．wasn’t it

C．did they

D．didn’t they