There is a peaceful and calm ________in the country, quite different from that of a big city.
He had thousands of students, many of ______ gained great success in their own field.
He asked a lot of questions, none of ______ was easy to answer.
He asked a lot of questions, and none of ______ was easy to answer.
He told me that he had two girl-friends, neither of _______ knew anything about the other.
He told me that he had two girl-friends, and neither of _______ knew anything about the other.