—Look! The lights in the teachers’ office are still on. Is Mr. Li working?—No. It _______ be Mr. Li. I saw him leave just now.
When he walks _______ the shop, he often stops ____ a look.
—I don’t like the ________trip, Mary .What about you? —I’m also ________ with it .
-He's never late for school, _______ he? -_______. He gets to school on time every day.
Betty writes ___________ than ___________ student in her classroom.
---Who is making much noise? ---It ____ be Timmy. He is sleeping now.