---Listen! Is Kate playing the piano in the room? ---No. It _________ be her. She has gone to London with her parents.
_____ he was tired , ____ he didn’t stop working .
Please _______the light when you leave the classroom.
—Can you answer this question? -- Sorry, I can _________ understand its meaning.
---Hurry up, _______ you will miss the exciting part of the film.
This book _______ be Li Lei’s. Look! Her name is on the cover.