He asked a lot of questions, none of ______ was easy to answer.

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.

George, with _______ I played tennis on Sundays, was a warm-hearted person.

This I did at nine o’clock, after _______ I sat reading the paper.

Ashdown forest, through _______ we’ll be driving, isn’t a forest any longer.

His house, for _______ he paid $10, 000, is now worth $50, 000.

None knows if _______ that boy, but if _______ him, her parents will be disappointed.

– Can you tell me ___________?
– An engineer from Jinan Iron and Steel Plants．