tying sporelings to rocks

例句：

1. 1. She tied her shoes with apiece of string.
   她用一根绳子系上了她的鞋子。
2. 2. The children were tying the knots on their shoelaces.
   孩子们正在他们的鞋带打结。
3. 3.He tied his coat around his neck tokeep warm.
   他系紧了他的外套来保暖。