Talk to them in a nice way. But if they still refuse_______, call the police.
The teacher showed us ______________ the problem.
-- It’s dangerous to walk across the street carelessly.--You’re right. We can’t be ________ careful while crossing the street.
If we don’t study hard, we will in our class.
I don’t know if she ____________ if it _____________ tomorrow.
How much difficulty did you have ________________ this problem?