When you are planting trees, the trees ________ straight in the hole.

---You were out when I went to your house this morning. ---Oh, I _______ for a friend from England at the airport.

— Shirley, I know you ___________ a book about China, Have you finished it?— Not yet. Maybe next year.

I called you, but nobody answered. Where ________ you?

While Suzy ______ on the sofa, the phone rang.