Having arrived in the country, he found he had few occasions to speake Chinese.这里的having arrived共同构成过去完成式的分词形式。你可以看下主句的时态found，说明是一般过去式。而arrive in the country肯定比found（过去式）要早发生，所以就是“过去的过去”，也就是过去完成式了（就必须加have)。但是又不能直接用had arrived, 因为这是一整句话，只能用作状语形式，就变成了having arrived. 翻译：你原来的翻译就不错。我八级水平，相信我，没错的1