human: 提供三个被动语态的例子。
 bot: 被动语态是用来强调动作的接受者而不是执行者。例如：He was given a gift by his friend.（他收到了朋友送的礼物。）The letter was sent to the wrong address.（这封信寄错了地址。）The project was completed ahead of schedule.（这个项目提前完成了。）