— Who’s that boy reading in the garden? Is it David?— It ____________ be David. I saw him in the classroom just now.
---What do you think of our plan?---I think it’s reasonable. But_____Bob, what we did is a waste of time.
Everyone must stay at home_____the weather gets good.
Even though the tortoise moves_____than the rabbit, it beats the rabbit in the race.
---Let’s go to the concert tonight.---I’m afraid I can’t. My mom_____me these days and I don’t want to break my family rules any more.
Who do you think this black bag_____?