Have you realized the difficulty we have ____ the problem?

Do you know when we can go back home? —Sorry, I don’t. Because of the heavy snow storm, highways have been blocked and flights have been __________.

Is he still raising money for charity? –Yes. He neverhope of helping poor children.

Paul isn’t as ______ as Sandy. He often makes mistakes in his homework.

She has visited Hong Kong_______, but she wants to be there a_____ time.