Please keep the secret to ________, children! Don’t let anybody else know it.
The old lady didn’t know when the house caught fire.
— Don’t forget to close the door when you leave the room.— No, I .
Though I live in the forest . I don’t feel .
If there are trees, the air in our city will be cleaner.
Will there be more people in 100 years, do you think? , I hope.