以……为食____________________
He told me that he had two girl-friends, and neither of _______ knew anything about the other.
All of the flowers now raised here have developed from those _____ in the forest.
The modern history of Italy dates from 1860, ______ the country became united.
We will be shown around the city: schools, museums, and some other places, _______ other visitors seldom go.
The old building, behind _______ was a famous church, was _______ we used to work.