We can see light in his office. He___________ be in his office.

The careless man received a ticket for speeding . He ____ have driven so fast .

--- Will Helen come to my party tonight?--- I am not sure. She _______ go to the cinema with her father.

-----Must we clean the classroom now?------No ,you _______.

It is hard to say what kind of person he is．Sometimes he is very friendly; at other times he ___ be very cold．