an extraordinary session

• 临时会议

an extraordinary session的用法和样例：

例句

1. We're having an impromptu meeting.
   我们在开一个临时会议。
2. I was asked to attend an unscheduled meeting, so I have to cancel the appointment for this afternoon.
   因为我必须参加一个临时会议，所以不得不取消今天下午和您的约会。