--- ______ schoolbag is this?--It' s _________.
I think _______ is good for your health.
Don’t leave your books on the table.Please _______.
---If there are _______ people driving, there will be _______ air pollution. ---Yes, the air will be fresher.
While I _______ down the street, I _______ my classmates.
If it _______ tomorrow morning,we’ll go out for a picnic.