【正确答案】 A

【答案解析】解析：assemble v．集合，聚集；召集；装配(如：People began to assemble on the platform．If we can assemble everybody then we can leave．It took two hours to assemble the bicycle．)。participate(in)vi．参加。attend vt．出席。summon vt.召集，召唤；传讯，传唤。