---Look at the boy running on the playground. Is it David? ---It ______ be him. I saw him go to the teachers’ office just now.
Do you need more people ______ you______ the vegetables.
I have __________ my watch everywhere. But I cannot find it.
---What are you going to do this weekend? -----I’m going to help _____the city parks with my classmates to make them clean.
Mr. Wang _______drive to work, but now he _______there by bike to keep healthy.
— We weren’t able to any new suggestions. — Don't worry. We’ll try to figure it out.