给你一段英文文本和一个特定单词，要求你找到该单词在文本中的所有实例。输出应为每个实例的上下文和位置。


原始文本：The quick brown fox jumps over the lazy dog. The dog barked at the fox, but it was too late.
单词：fox
Instance 1:
Context: The quick brown fox jumps over the lazy dog.
Position: 16-18

Instance 2:
Context: The dog barked at the fox, but it was too late.
Position: 21-23