to call upon的用法和樣例：
例句
- The general's speech was pitched as a call to arms.
將軍的講話是一個要大家拿起武器的號召。 - He called on the workers to fight for their rights.
他號召工人為爭取自己的權利而鬥爭。 - Police have appealed for witnesses to come forward.
警方呼籲目擊者挺身而出。 - He turned a deaf ear to all requests for help.
他不理會一切求援的呼籲。 - Henry got a stomachache and asked to be excused.
亨利肚子疼請求離開一下。 - He appealed to his friends for support.
他請求朋友支持。
