a clarion call的用法和样例：
- To all the people present, his speech is a clarion call.
- Spring sounded the war drum, sounded a clarion call in!
- It is a clarion call to the Court to read the Copyright Clause with fresh attention and historical understanding.
- Party officials, preferring their heroes to be larger than life, have massaged history to imply that the meetings 30 years ago were a clarion call for reform and opening.
- A clarion call to resistance.