—Someone is knocking at the door. Is it Ann?
—It ________ be her. She is giving a performance at the theater now.
A.may | B.must | C.can't | D.mustn't |
—Someone is knocking at the door. Is it Ann?
—It ________ be her. She is giving a performance at the theater now.
A.may | B.must | C.can't | D.mustn't |