同学你好，该知识点来自沪江网校《英语零基础直达大学六级【爆款特惠班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
这里不必再加however了，离得太近了难免有重复的感觉。
When a plane crashed in the mountains, the only passengers, a young woman and her two baby daughters, were not hurt. However, it was midwinter and extremely cold. After putting the children in a case and covering them with clothes, (however, there was none), and the woman kept close to them all night. On hearing planes early next morning, the woman stamped out SOS in the snow, which was seen by a pilot. A message was sent and they were soon rescued by a helicopter.

祝同学学习进步~