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

We can eat in the dining hall. But we _______ eat in the classroom.

--- Listen! David is talking happily with his mother in the next room.　--- It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.

--- It’s so late. Our son______ be back!--- Don’t worry. I dare say he ______ have some extra work to do.

Lucy’s colour ________blue because she likes to be the leader, so it __________red.