You can’t imagine that a well-behaved gentleman _____ be so rude to a lady.

---Is that Lucy’s sister, Lily?---No, it _______ be her. She has gone to English.

— Must I answer this question in English?— No, you_________.

My sister met him at the cinema yesterday afternoon, so he       your lecture.

—Excuse me, where are we going to have our class meeting?—I’m not sure. Ask Li Hua, please. He _________ know.