Thousands of foreigners were to the Shanghai World Expo the day it opened.A. attendedB. a

问题补充：

Thousands of foreigners were to the Shanghai World Expo the day it opened.

A. attended

B. attained

C. attracted

D. attach

答案：

A. attended

B. attained

(答案→)C. attracted

D. attach

解析：动词辨析。A参加；B达到，实现，获得；C吸引；D附着；句意：在上海世博会开始的那一天，成千上万的外国人被吸引来参加。故C正确。