-There is someone knocking at the door.- It ______ be Jimmy, he has gone to ShangHai .

 --- What’s the weather like? --- Pretty hot and wet in the summer, but it _____ be quite cold in the winter. 

---Be polite . You _____ talk to the old like that !  ---Sorry , I won’t .

The World Wide Web is sometimes jokingly called the World Wide Wait because it _______ be very slow. 

--- The fog is so thick that the express way ____ have been closed. --- You are right. I ____ have thought of that. Now we have to take another road.