a trace of anger的用法和样例：
- Liana had a trace of anger in her voice, "She said it was going to be a treat for me!
- He spoke without a trace of emotion.
- There was barely a trace of salt in the soup.
- He always spoke with a trace of sarcasm.
- There isn't a trace of a smile on her face.
- There is barely a trace of salt in the soup.