The number of medical schools reached 18 in the early 1990s and ______ around that level ever since.( )
are remaining
have remained
is remaining
has remained
—Jackie, could you please repeat what I said just now? — Sorry, I ____.
I____ my homework at nine o'clock last Sunday morning.
Look at the pride on Tom's face. He ____ to have been praised by the manager just now.
Professor John will give us a lecture on how to learn English, but when and where ____ yet.
He asked me how much ____ on the mountain bike.