This book______Tom’s,because his name is on the book.

--- 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.

I can play basketball，but my sister ________．

—        I know by what time you want the project to be done?—By the day after tomorrow.      you finish it on time?

—Must I go there right now, mum?—No, you ____. You can go there tomorrow.