As a Chinese saying goes, a mountain ______ be too high or an ocean too deep. Therefore, there is no end to our self-improvement.
There’s no light on — they __________ be at home.
— Could I have a word with you, mum? — Oh dear, if you __________.
—Is Jack on duty today? —It __________ be him. It’s his turn tomorrow.
As you worked late yesterday, you __________ have come this morning.
— Must he come to sign this paper himself? — Yes, he __________.