“发电报”常见的英文表达是 “send a telegram” 。
例句：
He decided to send a telegram to inform his family of the good news.（他决定发一封电报把好消息告知家人。）
In the past, people used to send telegrams for urgent communication.（过去，人们常通过发电报来进行紧急沟通 。）