—Listen ! Helen is singing in the next room.—It _______ be Helen. She has gone to Beijing.

---Are you going to see the film with us?--- I’m not sure. I        go to the concert instead.

—Is that man Mr Hu?—That ______ be Mr Hu. Because he has gone to Japan with his wife.

—I can’t stop smoking, doctor.— For your health, I’m afraid you________.

—I’m sorry. I         at you at the other day.— Forget it. I was a bit out of control myself.