独立主格结构的题2、They--------,the meeting was held according to scheduleA、having all arrived B、arrivingC、all arrived D、have all arrived3.All the task having been fulfilled ahead of time（提前完成了）,they decided to go on holiday for a week.为什么用having
问题描述：
独立主格结构的题
2、They--------,the meeting was held according to schedule
A、having all arrived B、arriving
C、all arrived D、have all arrived
3.All the task having been fulfilled ahead of time（提前完成了）,they decided to go on holiday for a week.
为什么用having
答