用被动语态翻译：1.认真听老师讲课2.对老人讲话应该有礼貌3.在图书馆不允许说话

1.teachers should be listened to carefully2.The elders should be talked to politely3.Talking mustn't be allowed in the library.希望我的回答能帮助到你O(∩_∩)O哈!有不懂的继续问我噢~...