－Who’s that girl swimming in the pool? Is it Lucy?－It        be Lucy. She is sleeping in her bedroom now.

-I didn't go to the art show, because I lost my ticket．-You______have borrowed mine I didn't go to see it anyway

It has been announced that students _______ remain in their seats until all the papers have been collected.

  —Shall I inform him of the change of the schedule right now?—I am afraid you _______, in case he comes late for the meeting.

 Sorry I’m late. I ____ have turned off the alarm clock and gone back to sleep again.