---Look at the glasses on the desk. Are they David’s?---They      belong to him. I saw him go out with glasses just now.

These shoes aren’t comfortable. You __________ wear them.

Days later, my brother called to say he was all right, but _______say where he was.

--Listen! Is it Linda singing in the next room? --No, it __________ be her. She is still in Shanghai.

）The red bike _______be Hu’s.  She has a blue bike.