Beijing is one of ______ biggest cities in China.

We are now in senior three. I think it’s time we ______ more efforts for the college-entrance exams.

Mary isn’t here these days. Is she ill?—-. Her mother told me that she was in hospital.

There’s ___________ with my iPad. I need to ask someone _________it.

Julie was good at German, French and Russian, all of she spoke fluently.