---Miss Lee, I didn’t catch what you said. Could you tell me ______ again?---OK.
--Why don’t you read this book?--It’s not necessary to read this book .There isn’t useful in it .
--I don’t think teenagers should be allowed to smoke.-- .
You should really _______ smoking. It’s a terrible habit.
Sixteen-year-olds shouldn’t ______ to go to an Internet bar.
The more careful you are, ________ mistakes you will make. I think it’s true.