What do you mean _____ signing the letter for him?[ ]

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 __________.

.—____ did you leave the classroom? —____ I saw my daughter sit down and read her book.

The river is very long and it is about.

What’s your phone number? —________ 7284587.