across china为什么不加the

china前为什么不加the 国家名字前面,为什么有的要加the,有的不加. 如China the U.S.A 为什么英语中有些国家前要加the 而有些不加the 例如the USA China _China is in _ east of Asia China 前为什么不加the? It ____countrise across the world,including China. march across the park为什么用across? The dog's running across the grass.狗在草地上跑,为什么要加across?3Q pandas live in China.live为什么不加s? the little boy ran very quickly across the grass这句中quick为什么加 The Great Wall runs across the n_____ part of china look!The robber is climbing——the wall.为什么填over不填across? we were travelling across the channel里的trave为什么加ing