---If there are _____people driving, there will be ______air pollution.---Yes, the air will be fresher and cleaner.
In our school library, there a very small number of books on history, and in these years the mumber of them getting larger and larger.
I wonder if it tomorrow. If it tomorrow, I won’t go hiking.
The science teacher told us the light faster than the sound.
My father used to to work on foot, but now he is used to to work by bike.
Could you tell me ?