—I think the whole class is going on a field trip next Friday.—I’m not sure. ____________ has paid the transportation fee. 

If a book is in French, ____ will be a challenge for me．

Is there ______ in the room?

—Who is the classroom now?—     . All the students are on the playground(操场)

– Which of the e-mails ______ you have ever got is the greatest?– I really can’t decide. ______ of them are very wonderful.