Beijing is ______ old and beautiful city. It is ______capital of China.

Our teacher often keeps us _______ the classroom, so we should keep our classroom _______.

Is it necessary that he ____ to London but to New York?– I think so, but the problem is ____ he has refused to.

In my opinion, he is a(n) _____ person, that is, he says exactly what he thinks. [ ]

I have bought two ballpens, _______ writes well.