Look, the set of keys _ _ on the teacher’s desk.

How well do you know the Opera House?—I know the place very well. I ____ Sydney many times.

The Frenchman caught _______ a cold ______ he coughed day and night.[ ]

I like Britney Spears. She’s ________ favorite singer.

Is the physics problem _________?—- Yes, I can work it out _________.