Who’s the man over there? Is it Mr. Black?— It _________ be him. He’s much taller.

Can I come this afternoon or tomorrow morning?–is OK.I’m free today and tomorrow.

Is this the first time you _____Chengdu ?—–No. But the first time I _____here, the city wasn’t so beautiful.

. —I have never spoken ill of Mary. — ____________ you don’t like her.

_____did the space flight last? —Twenty-one hours.[ ]