Is______necessary to change trains at Beijing?
This book is worth _____.
We should do ___ the teacher told us.
The number of the people in the world ______ growing faster and faster. A. is b. are C. have D. were
I’m sorry to have kept you ________ for a long time. A. wait b. to wait c. waiting D. to be waiting
The film __________ for ten minutes when we got to the cinema.