---Listen, Mum. I heard the footsteps. Is it Dad? ---It ___ be him. He’s gone to Beijing on business this morning.
–What did the radio say just now? - Sorry. I didn’t catch it. I _____ something else.
– Mum, do you know if Dad _____ a model plane for me? - I think he will do if he _____ free.
Last month, doctors used a 3-D printer to rebuild the face of a person ____ had a bad accident.
- Shall we climb Nanshan this weekend? - Good idea! It’s not high. It’s about _____ high.
It’s widely known that you won’t achieve success _____ you work hard.