Who ________ that played a trick on the new English teacher?
—Is Bob still a volunteer? —No, but he _____. He worked for the 2008 Beijing Olympic Games.
You’d better _______ because I’m busy writing a letter to my parents.
Last month we students all had some great speeches. The headmaster together with some other teachers __________ to attend it, too.
---Is Johnson on duty today? ---It ________ be him, but I’m not sure.
Mary’s mother told her daughter not to spend too much time surfing the Internet, but ______ didn’t help.