The headmaster who had the grand ceremony waved to the crowds with a smile .
A. included
B. joined
C. introduced
D. attended
网友回答
A. included
B. joined
C. introduced
(答案→)D. attended
解析：include包括；join参加（指参加某个组织或团体）；introduce介绍；attend参加（可指参加会议）。这里指参加一个盛大的仪式所以应选D。