Personal computers were in use in China when Amy visited the country in twentieth century(世纪).

It seems that you are familiar with this city.—I _____ English in a high school here for three years. It’s grerat to be back!

The question ______ at the next meeting will be a hard one. [ ]

You_____right,butIdon’tthinkyouare.

Which is ________, the sun, the moon or the earth—Of course the moon is.