Susan’s parents bought a large house with a swimming pool. It ______be very expensive.

---Could I have a word with you, mum? ----Oh, dear, if you ______.

My sister met him at the Grand Theatre yesterday afternoon，so he ________ your lecture.

— What do you want to eat for lunch? I will prepare it earlier today. — You_____, mum. Let’s go out to have something different. 

—There's someone knocking on the door．Who        it be?—It must be Mary．She promised to be here at 8：00．