When we are in a new place, we must __our manners and try to follow the customs of the place.
An awful accident, however, _____occur the other day.
It was probably at that moment _____ I understood what kindness really was.
—What was it that caused the party to be put off? —________ the invitations.
Who ________ that played a trick on the new English teacher?
—Where did you pick up the stamp? —It was at the post office ________ we worked in the summer vacation.