下列事件反映发展主题的是（ ）①巴以冲突②G20峰会商讨应对金融危机③中国——东盟自由贸易区全面启动④***与奥巴马共同出席核安全峰会
例：If I were in your position，I would pay close attention.
→Were I in your position，I would pay close attention.
