Shall we go hiking this Sunday? －Sorry, I _______. I’ll have to take a piano lesson.
Someone is knocking at the door. Who may it be? —It ______ be Tom. He is still in the school.
When do you go shopping?—I usually go shopping Sunday mornings.[ ]
Peter, did you hear any noise?－Sorry, I ________ newspapers.
It’s not right ________others’ homework.