This book ______ , because his name is on the book. 

The man ______ be my father. My father is much taller.

When Harry was at college, he ________ go to the reading room after supper every day.

 -- Must I come here at eight o’clock?                                           -No, you ____. You may come a little later.                                      

 We all know that we ________ our carbon footprint, but I suspect that many people wouldn't be prepared to go as far as Joan Pick, a retired scientist living in south London.