Definition: In this task, you are given a sentence. You must judge whether a single noun or verb has been replaced with another word with the same part of speech. The inversion would result in the sentence sounding unnatural, So unnatural sentences will be considered changed. Label the instances as "Original" or "Changed" based on your judgment.
Input: Several minutes later when Zac came on the line , they exchanged salutes and a few words before Neil explained what he had found to Zac .
