She would run off into the countryside, disappear for hours, then come back obviously having had a great time somewhere.
这个句子最后一句come back + doing这种语法，不懂。请老师解释一下。

她往往偷偷跑到乡下，消失数小时后，又回来了，明显看得出来，她在某个地方玩得很开心。

having had a great time somewhere是ing分词形式作方式状语从句，修饰或说明come回来时的伴随情况。下面给出用法和例句，供参阅：


【例】He wrote a letter telling me that he would be assigned to join in the military parade on National Day.
他写信告诉我，他被指派要参加国庆大阅兵。
【例】She came to her hometown having got a hard-won Olympic gold medal in swimming.
她带着那枚得来不易的奥运游泳金牌回到了故乡。