研究型Letter应聚焦一个具体且具新意的实验观察或数据点，避免内容泛泛。评论型Letter最好针对近期（如三个月内）刊物中的文章进行回应，这样更能引起编辑兴趣 。总之主题要“快”“新”“精”。

BEIJING, Sept. 8 (Xinhua) -- Chinese President Xi Jinping on Monday sent a congratulatory letter to the 25th China International Fair for Investment and Trade (CIFIT), which opened in Xiamen, east ...

BEIJING, Sept. 5 (Xinhua) -- Chinese President Xi Jinping on Friday sent a congratulatory letter to the World Smart Industry Expo 2025, which opened in southwest China's Chongqing Municipality.