北京研彩大票现代远程教育 ·2.A--A--B型 beat beat beaten 打 3.A-B-A型 come came come 来 become became become 变 run ran run 跑• ⒉ A---A---B型 • beat beat beaten 打 • ⒊ A---B---A型 • come came come 来 • become became become 变 • run ran run 跑