After Mandela was free (自由的) in 1990, he chose to shake hands with the people ________ wanted to kill him.
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.