An experienced doctor usually judges a patient’s illness according to the various________.
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.
Her sons, both of ______ work abroad, will come back home this summer.