31．—What’s the matter with Christine? —A letter from her parents in California________an attack of homesickness.

Our house stands alone ______ the street.

Steven, could you help me_______ when the plane will take off on the Internet-I’m sorry, my computer doesn’t work.

He ____ a lot of time ____ his homeworkevery day.

I won’t go to the concert because I _______ my ticket.