he was busy writing a story,olny stopping once in a while to smoke a cigarette
这句为什么是伴随状语,伴随状语不应该是2个动作同时发生吗?
Having suffering from heart trouble for years,professor white has to tale some medicine with him wherever he goes.这句为什么用Having done,没看出动作有先后.解释下Having done 用法,还有Having done一般用于哪种状语从句.
一直搞不懂的问题,请各位英语达人解答下,