【明報專訊】YESTERDAY Taiwan President Tsai Ing-wen wrapped up her visit to four Central American countries and returned to Taipei. In that trip she agreed to provide Guatemala US$50 million for building highways and bought sixteen containers of Salvadorean coffee beans but achieved little else. Nevertheless, some of the things she did in the US when she was in transit there newly clouded Sino-US relations and frosted cross-strait relations, which had frozen.