As we all know, the advantage _______ is good for students’ self-improvement.
He told me that he had two girl-friends, neither of _______ knew anything about the other.
He asked a lot of questions, and none of ______ was easy to answer.
He asked a lot of questions, none of ______ was easy to answer.
6. He had thousands of students, many of ______ gained great success in their own field.
I met the fruit-pickers, several of _______ were still university students.