21. It can’t be denied that the Diaoyu Islands are _______ part of China and what some Japanese have done recently is actually a defence against _______ Chinese people.
A. a; / B. a; the C. the; / D. /; the
22. -- Have you been to the Great Wall?
-- Perhaps not in my memory. _______, it might have been during my early childhood.
A. If any B. If ever C. If once D. If not
