四、六级难句攻关（35）

摘要

1.President Barack Obama drew a clear redline last August when he threatened di-rect military action if Syrian PresidentBashar Assad unleashed chemical or bio-logical weapons against rebels seeking totopple him.（Chicago Tribune,April25,2013）翻译：去年八月,巴拉克·奥巴马总统鲜明地表达了美国的立场,扬言会采取直接的军事行动,