As long as you’ve paid ____ advance we won’t charge you ____ delivery.
Why many adolescents have trouble communicating with their parents lies in _______we call “generation gap .”
I _______less than a pound a week when I first started work .
_______the cost ,the project will take a lot of time as well .
These professors had interrupted their own research to accept an invitation to _______in an unusual experiment .
I really don’t know why he hates everything we _______.