— Susan, would you like to go hiking with us this afternoon?— I'd love to, but I study for a test.A. may B. have to C. can
---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.
--- _______ I come back before 6 o’clock?---No,you _______.But you _______ be back later than 7 o’clock.
---What’s up? ---There is _______ with my computer. It doesn’t work.