− Do you know the most ancient city in China ─ Xi’an well? − No, this is the first time I ___________ here.

I think that this meal was well worth _______ was charged for it.

What difficulty do you have      the poor children from the poor village?

When you’ve finished school, don’t forget to come back to visit your school, ______?

—You look unhappy， my son?—I’m wondering how long it’ll be          we come to China again.