Cultural exchange ________ better understanding.
He said it was this classroom _______ he found his lost watch and _____ he would take good care of it from then on.
Henry set up a club for football fans, _____ he invited all his friends.
Tom’s pay depends on ______ the factory.
The old couple have been married for 40 years and never once _______ with each other.
---What do you think of my homework? ---Good work,________ a few slight mistakes.